// 闰年判断的两种条件:1. 能被400整除    2. 能被4整除不能被100整除

#define  _CRT_SECURE_NO_WARNINGS 1 #include<stdio.h> #include<math.h> int main() {

    int year, month;

    while (scanf("%d %d", &year, &month) != EOF)

    {

        switch (month)

        {

        case 2: 

            if (year % 400 == 0 || year % 4 == 0 && year % 100 != 0)

                printf("29\n");

            else

                printf("28\n");

break;

        case 4:

        case 6:

        case 9:

        case 11: printf("30\n"); break;

        default: printf("31\n"); break;

        }

    }

    return 0; }