程序代码：

#include<stdio.h>
#include<stdlib.h>
long long f(long long i,int n)
{
    if(i==1||n==0) return 1;
    else return (f(i-1,n)+f(i,n-1))%1000003;
}

int main()
{
    long long n;
    while(scanf("%lld",&n)!=EOF)
    {
        printf("%lld\n",f(n,4));
    }
}