mod = 998244353


def main():
    import sys
    input = sys.stdin.readline

    T = {"R": 0, "G": 1, "B": 2}

    N, K = map(int, input().split())
    ans = [""] * (N + 10)
    for _ in range(K):
        a, c = input().split()
        a = int(a)
        ans[a-1] = c
    for i in range((N // 3) + 1):
        cnt = [0] * 3
        for j in range(3):
            s = ans[i * 3 + j]
            if s == "R":
                cnt[0] += 1
            elif s == "G":
                cnt[1] += 1
            elif s == "B":
                cnt[2] += 1
        # j = 0
        if ans[i * 3] == "":
            if cnt[0] == 0:
                ans[i * 3] = "R"
                cnt[0] += 1
            elif cnt[1] == 0:
                ans[i * 3] = "G"
                cnt[1] += 1
            else:
                ans[i * 3] = "B"
                cnt[2] += 1
        # j = 1
        if ans[i * 3 + 1] == "":
            if cnt[0] == 0:
                ans[i * 3 + 1] = "R"
                cnt[0] += 1
            elif cnt[1] == 0:
                ans[i * 3 + 1] = "G"
                cnt[1] += 1
            else:
                ans[i * 3 + 1] = "B"
                cnt[2] += 1
        else:
            s = ans[i * 3 + 1]
            if cnt[T[s]] > 1:
                cnt[T[s]] -= 1

                if cnt[0] == 0:
                    ans[i * 3 + 1] = "R"
                    cnt[0] += 1
                elif cnt[1] == 0:
                    ans[i * 3 + 1] = "G"
                    cnt[1] += 1
                else:
                    ans[i * 3 + 1] = "B"
                    cnt[2] += 1
        # j = 2
        if ans[i * 3 + 2] == "":
            if cnt[0] == 0:
                ans[i * 3 + 2] = "R"
                cnt[0] += 1
            elif cnt[1] == 0:
                ans[i * 3 + 2] = "G"
                cnt[1] += 1
            else:
                ans[i * 3 + 2] = "B"
                cnt[2] += 1
        else:
            s = ans[i * 3 + 2]
            if cnt[T[s]] > 1:
                cnt[T[s]] -= 1

                if cnt[0] == 0:
                    ans[i * 3 + 2] = "R"
                    cnt[0] += 1
                elif cnt[1] == 0:
                    ans[i * 3 + 2] = "G"
                    cnt[1] += 1
                else:
                    ans[i * 3 + 2] = "B"
                    cnt[2] += 1

    print("".join(ans[:N]))


if __name__ == '__main__':
    main()