import java.util.Scanner;
import java.util.Arrays;

public class Main{
public static void main(String[] args){
Scanner scan=new Scanner(System.in);
int k=scan.nextInt();
int a=scan.nextInt();
int b=scan.nextInt();

int sum=0;
if(a%k==0){
    sum=sum+1;
}else if(b%k==0){
    sum=sum+1;
}else if(b/k-a/k>=1){
    sum=sum+1;
}

if(sum==1){
    System.out.println("OK");
}
if(sum==0){
    System.out.println("NG");
}

}
} import java.util.Scanner; Scanner java.util import java.util.Arrays; Arrays java.util public class Main{
public static void main(String[] args){
Scanner scan=new Scanner(System.in);
int k=scan.nextInt();
int a=scan.nextInt();
int b=scan.nextInt();

int sum=0;
if(a%k==0){
    sum=sum+1;
}else if(b%k==0){
    sum=sum+1;
}else if(b/k-a/k>=1){
    sum=sum+1;
}

if(sum==1){
    System.out.println("OK");
}
if(sum==0){
    System.out.println("NG");
}

}
} Main public static void main(String[] args){
Scanner scan=new Scanner(System.in);
int k=scan.nextInt();
int a=scan.nextInt();
int b=scan.nextInt();

int sum=0;
if(a%k==0){
    sum=sum+1;
}else if(b%k==0){
    sum=sum+1;
}else if(b/k-a/k>=1){
    sum=sum+1;
}

if(sum==1){
    System.out.println("OK");
}
if(sum==0){
    System.out.println("NG");
}

} main {
Scanner scan=new Scanner(System.in);
int k=scan.nextInt();
int a=scan.nextInt();
int b=scan.nextInt();

int sum=0;
if(a%k==0){
    sum=sum+1;
}else if(b%k==0){
    sum=sum+1;
}else if(b/k-a/k>=1){
    sum=sum+1;
}

if(sum==1){
    System.out.println("OK");
}
if(sum==0){
    System.out.println("NG");
}

} Scanner scan=new Scanner(System.in); scan new Scanner(System.in) int k=scan.nextInt(); k scan.nextInt() scan.nextInt scan int a=scan.nextInt(); a scan.nextInt() scan.nextInt scan int b=scan.nextInt(); b scan.nextInt() scan.nextInt scan int sum=0; sum 0 if(a%k==0){
    sum=sum+1;
}else if(b%k==0){
    sum=sum+1;
}else if(b/k-a/k>=1){
    sum=sum+1;
} a%k==0 a%k a k 0 {
    sum=sum+1;
} sum=sum+1 sum sum+1 sum 1 if(b%k==0){
    sum=sum+1;
}else if(b/k-a/k>=1){
    sum=sum+1;
} b%k==0 b%k b k 0 {
    sum=sum+1;
} sum=sum+1 sum sum+1 sum 1 if(b/k-a/k>=1){
    sum=sum+1;
} b/k-a/k>=1 b/k-a/k b/k b k a/k a k 1 {
    sum=sum+1;
} sum=sum+1 sum sum+1 sum 1 if(sum==1){
    System.out.println("OK");
} sum==1 sum 1 {
    System.out.println("OK");
} System.out.println("OK") System.out.println System.out System System.out "OK" if(sum==0){
    System.out.println("NG");
} sum==0 sum 0 {
    System.out.println("NG");
} System.out.println("NG") System.out.println System.out System System.out "NG" String[] args args public class Main{
public static void main(String[] args){
Scanner scan=new Scanner(System.in);
int k=scan.nextInt();
int a=scan.nextInt();
int b=scan.nextInt();

int sum=0;
if(a%k==0){
    sum=sum+1;
}else if(b%k==0){
    sum=sum+1;
}else if(b/k-a/k>=1){
    sum=sum+1;
}

if(sum==1){
    System.out.println("OK");
}
if(sum==0){
    System.out.println("NG");
}

}
} public class Main{
public static void main(String[] args){
Scanner scan=new Scanner(System.in);
int k=scan.nextInt();
int a=scan.nextInt();
int b=scan.nextInt();

int sum=0;
if(a%k==0){
    sum=sum+1;
}else if(b%k==0){
    sum=sum+1;
}else if(b/k-a/k>=1){
    sum=sum+1;
}

if(sum==1){
    System.out.println("OK");
}
if(sum==0){
    System.out.println("NG");
}

}
} Main
import java.util.Scanner;
import java.util.Arrays;

public class Main{
public static void main(String[] args){
Scanner scan=new Scanner(System.in);
int k=scan.nextInt();
int a=scan.nextInt();
int b=scan.nextInt();

int sum=0;
if(a%k==0){
    sum=sum+1;
}else if(b%k==0){
    sum=sum+1;
}else if(b/k-a/k>=1){
    sum=sum+1;
}

if(sum==1){
    System.out.println("OK");
}
if(sum==0){
    System.out.println("NG");
}

}
}