#include<stdio.h>
void main()
{
int y,m,d;
printf("please input year,month=");
scanf("%d%d",&y,&m);
d=0;
switch(m)
{
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:
printf("d=31");
break;
case 4:
case 6:
case 9:
case 11:
printf("d=30");
break;
case 2:
if (y%4==0 && y%100!=0 || y%400==0)
printf(" d=29");
else
printf("d=28");
}
}
