백준 C++ 1924번

#include <iostream>

using namespace std;

int main(void)
{
	int total,tmp;
	int x,y;
	int xx[] = {0,31,28,31,30,31,30,31,31,30,31,30};
	cin >> x >> y;
	
	if(x<1 || x > 12 || y<1 || y > 31)
		return -1;
	if(x==2 && y>28)
		return -1;
	if(x==4 && y==31)
		return -1;
	if(x==6 && y==31)
		return -1;
	if(x==9 && y==31)
		return -1;
	if(x==11 && y==31)
		return -1;
		
	for(int i=0;i<x;++i)
		tmp += xx[i];
		
	total = y + tmp;
	
	switch (total%7)
	{
		case 6 :
			cout << "SUN";
			break;
		case 0 :
			cout << "MON";
			break;
		case 1 :
			cout << "TUE";
			break;
		case 2 :
			cout << "WED";
			break;
		case 3 :
			cout << "THU";
			break;
		case 4 :
			cout << "FRI";
			break;
		case 5 :
			cout << "SAT";
			break;
		}
	cout << endl;
		
	return 0;
	
		
}