#include <stdio.h> int F(int n) { if(n==1||n==2) return 1; else return F(n-1)+F(n-2); } int main() { int n=0; scanf("%d",&n); //1 2 3 4 5 6 7 8 //1 1 2 3 5 int sum=F(n); printf("%d",sum); return 0; }