A = gets.rstrip
B = gets.rstrip
ans = if A == '0' || B == '0' || (
         A =~ /^[1-9]+\d*$/ && B =~ /^[1-9]+\d*$/ &&
         0 <= A.to_i && A.to_i <= 12345 &&
         0 <= B.to_i && B.to_i <= 12345)
        'OK'
      else
        'NG'
      end
puts ans