#!/usr/bin/env python3
# -*- coding: utf-8 -*-

# https://qiita.com/e869120/items/eb50fdaece12be418faa
# http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_10_A&lang=ja


def main():
    n = int(input().strip())
    print(fib(n))


def fib(n):
    dp = [1] * (n + 1)
    for i in range(2, n + 1):
        dp[i] = dp[i - 1] + dp[i - 2]
    return dp[n]


if __name__ == '__main__':
    main()
 def main():
    n = int(input().strip())
    print(fib(n)) main n = int(input().strip()) n int(input().strip()) int input().strip() ().strip () input strip print(fib(n)) print fib(n) fib n def fib(n):
    dp = [1] * (n + 1)
    for i in range(2, n + 1):
        dp[i] = dp[i - 1] + dp[i - 2]
    return dp[n] fib dp = [1] * (n + 1) dp [1] * (n + 1) [1] 1 n + 1 n 1 for i in range(2, n + 1):
        dp[i] = dp[i - 1] + dp[i - 2]
     i range(2, n + 1) range 2 n + 1 n 1 dp[i] = dp[i - 1] + dp[i - 2] dp[i] dp i dp[i - 1] + dp[i - 2] dp[i - 1] dp i - 1 i 1 dp[i - 2] dp i - 2 i 2 return dp[n] dp[n] dp n n n if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def fib(n):
    dp = [1] * (n + 1)
    for i in range(2, n + 1):
        dp[i] = dp[i - 1] + dp[i - 2]
    return dp[n] def fib(n):
    dp = [1] * (n + 1)
    for i in range(2, n + 1):
        dp[i] = dp[i - 1] + dp[i - 2]
    return dp[n] fib def main():
    n = int(input().strip())
    print(fib(n)) def main():
    n = int(input().strip())
    print(fib(n)) main
#!/usr/bin/env python3
# -*- coding: utf-8 -*-

# https://qiita.com/e869120/items/eb50fdaece12be418faa
# http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_10_A&lang=ja


def main():
    n = int(input().strip())
    print(fib(n))


def fib(n):
    dp = [1] * (n + 1)
    for i in range(2, n + 1):
        dp[i] = dp[i - 1] + dp[i - 2]
    return dp[n]


if __name__ == '__main__':
    main()

