#include <stdio.h> int main() { int n; scanf("%d",&n); if(n1) { printf("1\n"); return 0; } if(n2) { printf("2\n"); return 0; } int a=1; int b=2; int current; for(int i = 3;i<=n;i++) { current=a+b; a=b; b=current; } printf("%d\n",a); return 0; }