题解

#include <bits/stdc++.h>
using namespace std;
int main(){
    int y,m;
    bool run=0;
    cin>>y>>m;
    if(y%4==0 && y%100!=0 || y%400==0){
        run=1;
    }
    if(m==1 || m==3 || m==5 || m==7 || m==8 || m==10 || m==12){
        cout<<31;
    }else if(m==2){
        if(run==1){
            cout<<29;
        }else{
            cout<<28;
        }
    }else{
        cout<<30;
    }
    return 0;
}