#!/usr/bin/env python3

from statistics import mean
from subprocess import DEVNULL, run
from sys import argv, exit
from time import perf_counter


def benchmark(cmd, N=10):
    times = []
    for _ in range(N):
        start = perf_counter()
        run(cmd, shell=True, stdout=DEVNULL, stderr=DEVNULL)
        times.append(perf_counter() - start)
    return mean(times)


if __name__ == "__main__":
    if len(argv) < 2:
        print("usage: python3 bench.py 'cmd' [N]")
        exit(1)
    cmd = argv[1]
    N = int(argv[2]) if len(argv) > 2 else 10
    print(f"{benchmark(cmd, N):.4f}")