#include <iostream>
#include <conio.h>

using namespace std;

int main() {
	int thang;
	cout<<"Nhap vao thang: "; cin>>thang;
	switch (thang) {
		case 1:
		case 3:
		case 5:
		case 7:
		case 8:
		case 10:
		case 12: cout<<"Thang co 31 ngay"; break;
		case 4:
		case 6:
		case 9: cout<<"Thang co 30 ngay"; break;
		case 11:
		case 2: cout<<"Thang co 28 ngay"; break;
		default: cout<<"Thang nhap vao khong hop le";
	}
	return 0;
}