n, k = map(int, input().split())
ac = ["F"]*n
for _ in range(k):
    a, c = input().split()
    ac[int(a)-1] = c
count = [0]*3
ans = ""
for i in range(n):
    if ac[i] == "F":
        j = count.index(min(count))
        count[j] += 1
        ans += "RGB"[j]
    else:
        j = "RGB".find(ac[i])
        if count[j] > min(count):
            j = count.index(min(count))
        count[j] += 1
        ans += "RGB"[j]
print(ans)