Problem:
Score: 100 points

Problem Statement

Takahashi the Jumbo will practice golf.

His objective is to get a carry distance that is a multiple of K, while he can only make a carry distance of between A and B (inclusive).

If he can achieve the objective, print OK; if he cannot, print NG.

Constraints

All values in input are integers.

1 \leq A \leq B \leq 1000

1 \leq K \leq 1000

Input

Input is given from Standard Input in the following format:

K
A B

Output

If he can achieve the objective, print OK; if he cannot, print NG.

Sample Input 1

7
500 600

Sample Output 1

OK

Among the multiples of 7, for example, 567 lies between 500 and 600.

Sample Input 2

4
5 7

Sample Output 2

NG

No multiple of 4 lies between 5 and 7.

Sample Input 3

1
11 11

Sample Output 3

OK

Solution in Ruby (2.7.1) (judge verdict: Accepted)

k = gets.split.map(&:to_i)
a,b=gets.split.map(&:to_i)

y = (b/k[0]).to_i+1
i = 1
for i in 1..y
    if (a <= k[0]*i) && (k[0]*i <= b)
        puts 'OK'
        break            
    end
    if i == y
        puts 'NG'
        break
    end
end