#include<iostream>

using namespace std;

int Fibonacci(int n){
    if(n == 0) return 0;
    else if(n == 1) return 1;
    else return Fibonacci(n - 1) + Fibonacci(n - 2);
}

int main(){
    int n;
    while(scanf("%d", &n) != EOF){
        printf("%d\n", Fibonacci(n));
    }
    return 0;
}