#include <bits/stdc++.h>

int toInt(char buf[256], int x) {
  if( buf[0] == '\0' ) return x;
  if( not ( '0' <= buf[0] and buf[0] <= '9' ) ) return -1;
  return toInt(&buf[1], x * 10 + (buf[0] - '0'));               
}

int main() {
  char buf1[256];
  char buf2[256];
  scanf("%s", buf1);
  scanf("%s", buf2);
  int a = toInt(buf1, 0);
  int b = toInt(buf2, 0);
  if( 0 <= a and a <= 12345 and 0 <= b and b <= 12345 and (strlen(buf1) == 1 or buf1[0] != '0') and (strlen(buf2) == 1 or buf2[0] != '0' ) ) {
    puts("OK");
  }
  else {
    puts("NG");
  }

  return 0;
}