Coloring cube

n = int(input())
pattern = "RGB"

out = ""
ix = 0
for i in range(n):
    thisblockstartswith = i % 3
    for j in range(n):
        thisrowstartswith = j % 3
        ix = ((j % 3) + (i % 3)) % 3
        for k in range(n):
            out += f"{pattern[ix]}"
            ix = (ix + 1) % 3
        out += "\n"
    out += "\n"

print(out)

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: TIME LIMIT EXCEEDED

Test 7

Verdict: TIME LIMIT EXCEEDED

Test 8

Verdict: TIME LIMIT EXCEEDED

Test 9

Verdict: TIME LIMIT EXCEEDED

Test 10

Verdict: TIME LIMIT EXCEEDED