Coloring cube

import java.io.IOException;
import java.io.StreamTokenizer;
import java.io.BufferedReader;
import java.io.InputStreamReader;

public class ColoringCube {

    public static void main(String[] args) throws IOException {

        StreamTokenizer in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
        in.nextToken();
        int n = (int) in.nval;
        StringBuilder sb = new StringBuilder();
        String pattern = "RGB";
        int ix = 0;
        for (int i = 0; i < n; i++) {
            int i3 = i % 3;
            for (int j = 0; j < n; j++) {
                ix = ((j % 3) + i3) % 3;
                for (int k = 0; k < n; k++) {
                    sb.append(pattern.charAt(ix) + " ");
                    ix = (ix + 1) % 3;
                }
                sb.append("\n");
            }
            sb.append("\n");
        }

        System.out.println(sb);
    }

}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED