import sys
readline = sys.stdin.readline

N, K = map(int, readline().split())
D = [[10 ** 18, 0]]
for i in range(K):
    A, c = readline().split()
    if c == "R":
        n = 0
    elif c == "G":
        n = 1
    else:
        n = 2
    D.append([int(A), n])
D.sort(reverse=True)
color = [0] * 3
ans = []
hat = ["R", "G", "B"]
for i in range(N):
    if max(color) == min(color):
        ind = 0
    else:
        for j in range(3):
            if color[j] == min(color):
                ind = j
                break
    temp = [0] * 3
    for j in range(3):
        temp[j] = color[j]
    temp[ind] += 1
    if D[-1][0] != i + 1:
        ans.append(hat[ind])
        color[ind] += 1
    else:
        A, c = D[-1]
        D.pop()
        if temp[c] == max(temp):
            ans.append(hat[ind])
            color[ind] += 1
        else:
            ans.append(hat[c])
            color[c] += 1
print(*ans, sep="")