import sys

int1 = lambda x: int(x) - 1

# input = lambda: sys.stdin.buffer.readline()
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
i1 = lambda: int1(input())
mi = lambda: map(int, input().split())
mi1 = lambda: map(int1, input().split())
li = lambda: list(mi())
li1 = lambda: list(mi1())
lli = lambda n: [li() for _ in range(n)]

INF = float("inf")
mod = int(1e9 + 7)
# mod = 998244353

n, k = mi()
t = [-1] * n
rgb = "RGB"
for i in range(k):
    a, c = input().split()
    a = int1(a)
    t[a] = rgb.index(c)
ans = []
cnt = [0, 0, 0]
for i in range(n):
    if t[i] != -1 and cnt[t[i]] == min(cnt):
        ans.append(rgb[t[i]])
        cnt[t[i]] += 1
    else:
        j = cnt.index(min(cnt))
        ans.append(rgb[j])
        cnt[j] += 1
print("".join(ans))