#include <stdio.h>
#include <stdbool.h>

int main(){
	int c[2];
	int a, i = 0;
	int vysledok;
	char riadok[999];
	char *endptr = NULL;
	bool first = true;
	bool second = false;
	while(1){
		a++;
		char* r = fgets(riadok,999,stdin);
		if(*r == '\n'){
			break;
		}else if(*r == ' ')
			continue;
		else if(*r == '+'){
			first = true;
			second = true;;
			continue;
		}else if(*r == '-'){
			first = false;
			second = false;
			continue;
		}else if(*r == '/'){
			first = true;
			second = false;
			continue;
		}else if(*r == '*'){
			first = false;
			second = true;
			continue;
		}else{
			float v = strtod(riadok,&endptr);
			c[i++] = v;
			continue;
		}
	}
	if(first == true && second == true)
		vysledok = c[0] + c[1];
	else if(first == false && second == false)
		vysledok = c[0] - c[1];
	else if(first == true && second == false)
		vysledok = c[0] / c[1];
	else if(first == false && second == true)
		vysledok = c[0] * c[1];
	if(vysledok == c[2])
		printf("OK\n");
	else
		printf("ZLE\n");
	return 0;
}