package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

type PerfectNumber struct {
	number       int
	stadardValue int
	sum          int
}

func (p PerfectNumber) Result() string {
	if p.sum == p.number*2 {
		return "OK"
	}
	return "NG"
}

func main() {
	var scan *bufio.Scanner
	scan = bufio.NewScanner(os.Stdin)
	scan.Scan()
	stringInput := scan.Text()
	number, err := strconv.Atoi(strings.TrimSpace(stringInput))
	if err != nil {
		panic(err)
	}
	perfectNumber := PerfectNumber{number: number, stadardValue: number}
	for i := 1; i <= number; i++ {
		if number%i == 0 {

			if i < perfectNumber.stadardValue {
				result := number / i
				perfectNumber.sum += i
				perfectNumber.sum += result
				perfectNumber.stadardValue = result
			} else {
				break
			}
		}
	}
	fmt.Print(perfectNumber.Result())
}