#include <stdio.h>

int main (){
	char riadok[999];
	char *endptr = NULL;
	char need;
	int i, a, vysledok = 0;
	float c[99];
	while(1){
		char* r = fgets(riadok,999,stdin);
		riadok[i++] = *r;
		if(*r == '\n')
			break;
	}
	int j = 0;
	do{
		if(riadok[j] == ' '){
			j++;
			continue;
		}else if(riadok[j] == '+'){
			need = riadok[j];
			j++;
			continue;
		}else if(riadok[i] == '/'){
			need = riadok[j];
			j++;
			continue;
		}else if(riadok[i] == '-'){
			need = riadok[j];
			j++;
			continue;
		}else if(riadok[j] == '*'){
			need = riadok[j];
			j++;
			continue;
		}else if(riadok[j] == '='){
			if(need == '+')
				vysledok = c[0] + c[1];
			else if(need == '-')
				vysledok = c[0] - c[1];
			else if(need == '/')
				vysledok = c[0] / c[1];
			else if(need == '*')
				vysledok = c[0] * c[1];
			j++;
			continue;
		}else{
			float v = strtod(riadok,&endptr);
			c[a] = v;
			a = a + 1;
		}
	}while(j < i);
	if(vysledok == c[2])
		printf("OK\n");
	else
		printf("ZLE\n");
}