C++ :

#include <iostream>
using namespace std;
int judge(int year)
 {
  if(year%4==0&&year%100!=0||year%400==0)
	  return 1;
  else
	  return 0;
}
int main()
{
	int n,y,a;
	int r[12]={31,29,31,30,31,30,31,31,30,31,30,31};
	int p[12]={31,28,31,30,31,30,31,31,30,31,30,31};
	cin>>n>>y;
	a=judge(n);

	if(a==1)
	    cout<<r[y-1]<<endl;
	else
		cout<<p[y-1]<<endl;
	return 0;

}

Pascal :

program t21245;
var y,m,d:integer;
begin
 readln(y,m);
 case m of
  1,3,5,7,8,10,12:d:=31;
  4,6,9,11:d:=30;
  2:
  if(y mod 4=0) and (y mod 100<>0)or(y mod 400=0)
    then d:=29 else d:=28;
  end;
 writeln(d);
end.