懒人代码

#include<bits/stdc++.h>
using namespace std;
const int INF=0x3f3f3f3f;
int const N=1e5+10;
int x,y;
int main(){
	cin>>x>>y;
	if(y==2){
		if(x%4==0&&x%100!=0||x%400==0){
			cout<<29;
			return 0;
		}else{
			cout<<28;
			return 0;
		}
	}
	if(y==1||y==3||y==5||y==7||y==8||y==10||y==12)cout<<31;
	else{
		cout<<30;
	}
	return 0;
}