A = gets.chomp
B = gets.chomp

a = A.to_i
b = B.to_i

cond1 = (0..12345).include?(a) && (0..12345).include?(b)
cond2 = a.to_s == A && b.to_s == B

if cond1 && cond2
  puts 'OK'
else
  puts 'NG'
end