#include <iostream>
#include <conio.h>
using namespace std;
int main()
{
    int n,d,y;
    cout<< "moi nhap thang can tim ";cin>> n;
    if ((n>=1)&&(n<=12))
    {
        switch (n)
        {
        case 1 :    d=31;break;
        case 2 :
        {
            cout<<"moi ban nhap nam hien tai ";cin>> y;
            if (y%4==0)
            {
                d=29;break;

            }
            else
            {
                d=28;break;
            }
        }
        case 3 :    d=31;break;
        case 4 :    d=30;break;
        case 5 :    d=31;break;
        case 6 :    d=30;break;
        case 7 :    d=31;break;
        case 8 :    d=31;break;
        case 9 :    d=30;break;
        case 10:    d=31;break;
        case 11:    d=30;break;
        case 12:    d=31;break;
        }
        cout<<"so ngay trong thang la: "<<endl <<d;
    }
    else
    {
        cout<< "thang khong ton tai";
    }
}