View Code of Problem 23

#include<iostream>

using namespace std;

int main(void){
    int big[91],small[91];
    big[1]=1;
    small[1]=0;
    for(int i=2;i<=90;i++){
        big[i]=small[i-1]+big[i-1];
        small[i]=big[i-1];
    }
    int n;
    while(~scanf("%d",&n),n){
        printf("%d\n",small[n]+big[n]);
    }
}