# -*- coding:utf-8 -*-

def solve():
    import sys

    N = int(sys.stdin.readline())

    dp = [None]*45
    dp[0], dp[1] = 1, 1

    def fib(n):
        if dp[n] is not None:
            return dp[n]
        dp[n] = fib(n-1) + fib(n-2)
        return dp[n]

    print(fib(N))


if __name__ == "__main__":
    solve()
 def solve():
    import sys

    N = int(sys.stdin.readline())

    dp = [None]*45
    dp[0], dp[1] = 1, 1

    def fib(n):
        if dp[n] is not None:
            return dp[n]
        dp[n] = fib(n-1) + fib(n-2)
        return dp[n]

    print(fib(N)) solve import sys sys N = int(sys.stdin.readline()) N int(sys.stdin.readline()) int sys.stdin.readline() sys.stdin.readline sys.stdin sys stdin readline dp = [None]*45 dp [None]*45 [None] None 45 dp[0], dp[1] = 1, 1 dp[0] dp 0 1 dp[1] dp 1 1 def fib(n):
        if dp[n] is not None:
            return dp[n]
        dp[n] = fib(n-1) + fib(n-2)
        return dp[n]

     fib if dp[n] is not None:
            return dp[n]
         dp[n] is not None dp[n] dp n None return dp[n] dp[n] dp n dp[n] = fib(n-1) + fib(n-2) dp[n] dp n fib(n-1) + fib(n-2) fib(n-1) fib n-1 n 1 fib(n-2) fib n-2 n 2 return dp[n] dp[n] dp n n n print(fib(N)) print fib(N) fib N if __name__ == "__main__":
    solve() __name__ == "__main__" __name__ "__main__" solve() solve def solve():
    import sys

    N = int(sys.stdin.readline())

    dp = [None]*45
    dp[0], dp[1] = 1, 1

    def fib(n):
        if dp[n] is not None:
            return dp[n]
        dp[n] = fib(n-1) + fib(n-2)
        return dp[n]

    print(fib(N)) def solve():
    import sys

    N = int(sys.stdin.readline())

    dp = [None]*45
    dp[0], dp[1] = 1, 1

    def fib(n):
        if dp[n] is not None:
            return dp[n]
        dp[n] = fib(n-1) + fib(n-2)
        return dp[n]

    print(fib(N)) solve
# -*- coding:utf-8 -*-

def solve():
    import sys

    N = int(sys.stdin.readline())

    dp = [None]*45
    dp[0], dp[1] = 1, 1

    def fib(n):
        if dp[n] is not None:
            return dp[n]
        dp[n] = fib(n-1) + fib(n-2)
        return dp[n]

    print(fib(N))


if __name__ == "__main__":
    solve()

