hdu 2018 母牛的故事

#include<stdio.h>

int main(void)

{

    int i,n,j,k;

    long long narr[60];

    narr[1]=1;

    narr[2]=2;

    narr[3]=3;

    narr[4]=4;

    narr[5]=6;

    for(i=6; i<55; i++)

    {

        narr[i]=narr[i-1]+narr[i-3];

    }

    while(scanf("%d",&n)!=EOF,n)

    {

        printf("%lld\n",narr[n]);

    }

    return 0;

}