diff --git a/Cargo.toml b/Cargo.toml
index 2bf8179..ec85626 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,5 +6,6 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+clap = { version = "4.5.35", features = ["derive"] }
 lll-rs = "0.2.0"
 rug = "1.27.0"
diff --git a/gen_values.py b/gen_values.py
index f5ab69a..f73c9a2 100644
--- a/gen_values.py
+++ b/gen_values.py
@@ -1,6 +1,28 @@
-from random import randint
-p = randint(100,1000)
-a = ["Integer::from("+str(p*randint(1,100)+randint(0,20))+"), " for _ in range(200)]
-for b in a:
-    print(b)
-print(p)
+import sys
+import random
+import argparse
+
+def generate_test_file(noise_bits, number):
+
+    p = random.randint(100, 1000)
+    while p % 2 == 0:
+        p = random.randint(100, 1000)
+
+    max_noise = (1 << noise_bits) - 1  # 2^noise_bits - 1
+
+    a = [str(p * random.randint(1, 100) + random.randint(0, max_noise)) for _ in range(number)]
+
+    print(noise_bits)
+
+    for b in a:
+        print(b)
+
+    print(f"// True p: {p}")
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description='Generate test input for AGCD computation')
+    parser.add_argument('--noise-bits', type=int, default=5, help='Number of noise bits (default: 5)')
+    parser.add_argument('--number', type=int, default=20, help='Number of numbers to generate (default: 20)')
+
+    args = parser.parse_args()
+    generate_test_file(args.noise_bits, args.number)
diff --git a/src/agcd.rs b/src/agcd.rs
index 8c0dda4..cf712ec 100644
--- a/src/agcd.rs
+++ b/src/agcd.rs
@@ -1,7 +1,7 @@
-use rug::Integer;
 use crate::matrix::Matrix;
 use crate::utils::abs;
 use lll_rs::l2::bigl2;
+use rug::Integer;
 
 pub fn agcd(ciphertexts: Vec<Integer>, noise_bits: usize) -> Integer {
     // 1. Build lattice matrix basis
diff --git a/src/file.rs b/src/file.rs
new file mode 100644
index 0000000..6848f8c
--- /dev/null
+++ b/src/file.rs
@@ -0,0 +1,52 @@
+use std::fs;
+use std::path::Path;
+use rug::Integer;
+use std::io;
+
+pub struct AgcdInput {
+    pub noise_bits: usize,
+    pub numbers: Vec<Integer>,
+}
+
+// Parse the input file, return noise_bits and numbers.
+pub fn parse_file(path: &Path) -> io::Result<AgcdInput> {
+    let content = fs::read_to_string(path)?;
+    let mut lines = content.lines();
+
+    // Parse noise_bits from first non comment line
+    let noise_bits = loop {
+        match lines.next() {
+            Some(first_line) => {
+                let trimmed = first_line.trim();
+                if trimmed.starts_with("//") {
+                    continue; // Skip comment lines
+                }
+                break trimmed.parse::<usize>()
+                    .map_err(|e| io::Error::new(
+                        io::ErrorKind::InvalidData,
+                        format!("First non-comment line must be noise_bits (usize): {}", e)
+                    ))?;
+            },
+            None => return Err(io::Error::new(
+                io::ErrorKind::InvalidData,
+                "Input file is empty or contains only comments"
+            )),
+        }
+    };
+
+    // Parse numbers from remaining lines
+    let numbers: Vec<Integer> = lines
+        .filter(|line| !line.trim().starts_with("//") && !line.trim().is_empty())   // ignore comment and empty lines
+        .filter_map(|line| line.trim().parse::<u64>().ok())
+        .map(Integer::from)
+        .collect();
+
+    if numbers.len() < 2 {
+        return Err(io::Error::new(
+            io::ErrorKind::InvalidData,
+            "Need at least 2 numbers to compute AGCD"
+        ));
+    }
+
+    Ok(AgcdInput { noise_bits, numbers })
+}
diff --git a/src/main.rs b/src/main.rs
index 8d64b9c..99a64b4 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,32 +1,42 @@
-use rug::Integer;
+mod agcd;
 mod lll;
 mod matrix;
 mod utils;
-mod agcd;
-use crate::agcd::agcd;
+mod file;
 
-fn main() {
-    // 1. Build lattice matrix basis
-    let ciphertexts = vec![
-Integer::from(32219),
-Integer::from(21254),
-Integer::from(16764),
-Integer::from(338),
-Integer::from(29960),
-Integer::from(23516),
-Integer::from(7084),
-Integer::from(26735),
-Integer::from(23195),
-Integer::from(11928),
-Integer::from(985),
-Integer::from(11916),
-Integer::from(13217),
-Integer::from(29966),
-Integer::from(14171),
-Integer::from(13211),
-Integer::from(23514),
-Integer::from(19643)
-    ];
-    let noise_bits = 2;
-    let _ = agcd(ciphertexts, noise_bits);
+use crate::agcd::agcd;
+use crate::file::parse_file;
+use clap::{Parser, Subcommand};
+use std::path::{Path, PathBuf};
+
+#[derive(Parser)]
+#[command(author, version, about, long_about = None)]
+#[command(propagate_version = true)]
+struct Cli {
+    #[command(subcommand)]
+    command: Commands,
+}
+
+#[derive(Subcommand)]
+enum Commands {
+    /// approximate GCD
+    Agcd {
+        /// (default './input.txt')
+        path: Option<PathBuf>,
+    },
+}
+
+fn main() -> std::io::Result<()> {
+    let cli = Cli::parse();
+
+    match &cli.command {
+        Commands::Agcd { path } => {
+            let path = path.as_deref().unwrap_or(Path::new("./input.txt"));
+            let input = parse_file(path)?;
+
+            let result = agcd(input.numbers, input.noise_bits);
+            println!("Approximate GCD with noise_bits={}: {}", input.noise_bits, result);
+        }
+    }
+    Ok(())
 }