#include <stdio.h>
#include <stdbool.h>
int main ()
{
	int c, vysledok, i = 0;
	int b[99];
	bool first = true;
	bool second = false;
	while(1){
		c = getchar();
		if(c == ' ' || c == '+' || c == '\n' || c == '-' || c == '/' || c == '*' || c == '='){
			if(c == '\n'){
				break;
			}else if(c == ' '){
				continue;
			}else if(c == '='){
				continue;
			}else if(c == '+'){
				first = true;
				second = true;
				continue;
			}else if(c == '-'){
				first = false;
				second = false;
				continue;
			}else if(c == '/'){
				first = true;
				second = false;
				continue;
			}else if(c == '*'){
				first = false;
				second = true;
				continue;
			}
		}else{
			c = 0;
			int r = scanf("%d",&c);
			b[i++] = c;
		}
	}
	if(first == true && second == true)
		vysledok = b[0] + b[1];
	else if(first == false && second == false)
		vysledok = b[0] - b[1];
	else if(first == true && second == false)
		vysledok = b[0] / b[1];
	else if(first == false && second == true)
		vysledok = b[0] * b[1];
	if(vysledok == b[2])
		printf("OK\n");
	else
		printf("ZLE\n");
	return 0;
}