#include <stdio.h> long long int Fib(int n, long long int n1,long long int n2) { if (n==0) { return n1; } return Fib(n-1,n2,n1+n2); } int main() { int n; while(scanf("%d",&n)!=-1) printf("%lld\n",Fib(n,0,1)); return 0; }