#include<stdio.h>
main()
{
int a,b,c;
printf("请分别输入年号和月份\n");
scanf("%4d %2d\n",&a,&b);
switch(b)
{case 1:c=31;
case 2:
{if (a%4==0&&a%100!=0||a%400==0)c=29;
else c=28; };break;
case 3:c=31;break;
case 4:c=30;break;
case 5:c=31;break;
case 6:c=30;break;
case 7:c=31;break;
case 8:c=31;break;
case 9:c=30;break;
case 10:c=31;break; case 11:c=30;break; case 12:c=31;break; printf("%d\n",c);} }