import sys
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
rec = False #再帰を使うときはこれをTrueにする
if rec:
    sys.setrecursionlimit(5 * 10 ** 5)
    from pypyjit import set_param
    set_param('max_unroll_recursion=-1')
inf = 2 ** 63 - 1
mod = 998244353

n, k = mi()

a = [None] * (n + (3 - n) % 3)
color = ['R', 'G', 'B']
for _ in range(k):
    i, c = input().split()
    i = int(i)
    a[i - 1] = c

ans = [None] * (n + (3 - n) % 3)

for i in range((n + (3 - n) % 3) // 3):
    now = set(color)

    for j in range(3):

        if a[3 * i + j] is not None and a[3 * i + j] in now:
            now.discard(a[3 * i + j])
            ans[3 * i + j] = a[3 * i + j]
            

    for j in range(3):
        if ans[3 * i + j] is None:
            ans[3 * i + j] = now.pop()
print(''.join(ans[:n]))