import sys,random,bisect
from collections import deque,defaultdict,Counter
from heapq import heapify,heappop,heappush
from itertools import cycle, permutations
from math import log,gcd

input = lambda :sys.stdin.readline().rstrip()
mi = lambda :map(int,input().split())
li = lambda :list(mi())



N,K = mi()
res = [""] * (N+3)
for _ in range(K):
    a,c = input().split()
    a = int(a)-1
    res[a] = c

for i in range(0,N,3):
    for S in permutations("RGB"):
        S = "".join(S)
        flag = True
        for j in range(3):
            if res[i+j] and res[i+j] not in S[:j+1]:
                flag = False
        if flag:
            res[i],res[i+1],res[i+2] = S[0],S[1],S[2]
            break

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