#!/usr/bin/env python3

import sys
print(sys.argv)

n = 35

def fib(x):
    if (x < 2):
        return x
    return fib(x-1) + fib(x-2)

def main():
    global n
    
    if len(sys.argv) > 1:
        n = int(sys.argv[1])

    print("{}\n".format(fib(n)))

if __name__ == "__main__":
    main()