N, K = map(int, input().split())
p = []
for i in range(K):
    a, b = map(str,input().split())
    p.append([int(a),b])
p.sort()
ans = ['R','G','B']*(N//3)+['R','G','B'][:N%3]
c = {j:i for i, j in enumerate('RGB')}

for a, b in p:
    if a%3==1:
        if ans[a-1]!=b:
            if a<N and ans[a]==b:
                ans[a-1],ans[a] = ans[a], ans[a-1]
                continue
            if a+1<N and ans[a+1]==b:
                ans[a-1],ans[a+1] = ans[a+1],ans[a-1]
                continue
            ans[a-1] = b
    elif a%3==2:
        if ans[a-1]!=b:
            if a-2>=0 and ans[a-2]==b:continue
            if a<N and ans[a]==b:
                ans[a-1],ans[a] = ans[a],ans[a-1]
                continue
            ans[a-1]=b


debug = [[0]*3 for _ in range(N)]
for i in range(N):
    debug[i][c[ans[i]]] += 1
    if i>0:
        for j in range(3):
            debug[i][j] += debug[i-1][j]

for a, b in p:
    assert debug[a-1][c[b]] == max(debug[a-1])
print(''.join(ans))