#include <stdio.h>

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