HDU 2005 第几天？

#include <bits/stdc++.h>

using namespace std;

int rn[15]= {0,31,29,31,30,31,30,31,31,30,31,30,31};
int pn[15]= {0,31,28,31,30,31,30,31,31,30,31,30,31};

int main()
{
    int year,mon,day;

    while(~scanf("%d/%d/%d",&year,&mon,&day))
    {
        int sum=0,res=0;
        if((year%4==0&&year%100!=0)||year%400==0)
        {
            //cout<<"yes"<<endl;
            for(int i=1; i<=mon; i++)
            {
                sum+=rn[i-1];
            }
        }
        else
        {
            //cout<<"no"<<endl;
            for(int i=1; i<=mon; i++)
            {
                sum+=pn[i-1];
            }

        }
        res=sum+day;
        //cout<<rn[1]<<endl;
        printf("%d\n",res);
    }
    return 0;
}