#include <iostream>
#include <conio.h>
#include <math.h>
using namespace std;
int main()
{
    int dd,mm,yy,ddmax;
    cout<<"Chon ngay : ";
    cin>>dd;
    cout<<"Chon thang : ";
    cin>>mm;
    cout<<"Chon nam : ";
    cin>>yy;
    if ((yy < 0) || (mm > 12) || (dd <  0) || (dd > 31) || (mm < 0))
    cout<<"KHONG HOP LE";
    else
    {

     switch (mm)
        {
        case 1:
        case 3:
        case 5:
        case 7:
        case 8:
        case 10:
        case 12:
        ddmax=31;
        break;
        case 2:
            if ((yy % 4 == 0) && (yy % 100 != 0) || (yy % 400 == 0))
            ddmax=29;
            else
            ddmax=28;
        case 4:
        case 6:
        case 9:
        case 11:
         ddmax=30;
         break;

        default:
        {
            cout<<"KHONG HOP LE";
        }
        }
        if (dd < ddmax)
        {
            cout<<"Ngay hop le";
        }
        else
        {
            cout<<"Ngay khong hop le";
        }
    }
    getch();
    return  0;
}