题解

#include<iostream>
using namespace std;
int Feb29(int y){
    return (y%400==0||y%4==0&&y%100!=0);
}
int days(int y,int m){
    if (m==1||m==3||m==5||m==7||m==8||m==10||m==12) return 31;
    if (m==4||m==6||m==9||m==11) return 30;
    return 28 + Feb29(y);
}
int main(){
    int y,m;
    cin >> y >> m;
    cout << days(y,m) << endl;
    return 0;
}