fix default pattern argument

main.py

@@ -17,7 +17,7 @@ def main():
 
     parser = argparse.ArgumentParser(description='A basic stuck-at fault simulator.')
     parser.add_argument('-t', '--tlib', default='SKY130', help=f'Techlib for verilog circuit. Default: SKY130, available: {sorted(techlib_by_name.keys())}.')
-    parser.add_argument('-p', '--patterns', default=1024, help='Pattern file or number of random patterns to simulate. Default: 1024.')
+    parser.add_argument('-p', '--patterns', default='1024', help='Pattern file or number of random patterns to simulate. Default: 1024.')
     parser.add_argument('-o', '--output', default=None, help='')
     parser.add_argument('--seed', type=int, default=42, help='Random seed for reproducibility. Default: 42.')
     parser.add_argument('circuit', help='Gate-level verilog, bench, or nix package to import. See available packages: "nix flake show github:s-holst/benchmark-circuits".')