求助

#include<bits/stdc++.h>
using namespace std;
int year,month;
int a[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
int main()
{
    cin>>year>>month;
    if((year%4==0&&year%100!=0)||a%400==0)a[2]=29;
    cout<<a[month];
    return 0;
}