#include <iostream>
using namespace std;

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

int main() {
    int n;
    while (cin >>n) { 
        cout<<Fib(n)<<endl;
    }
}