import sys
from operator import itemgetter
from collections import defaultdict, deque
import heapq
from heapq import heapify, heappop, _heapify_max, heappush
from bisect import bisect_left, bisect_right
import math
import itertools
import copy

stdin=sys.stdin
#sys.setrecursionlimit(10 ** 7)
#import pypyjit
#pypyjit.set_param('max_unroll_recursion=-1')

ip=lambda: int(sp())
fp=lambda: float(sp())
lp=lambda:list(map(int,stdin.readline().split()))
sp=lambda:stdin.readline().rstrip()
Yp=lambda:print('Yes')
Np=lambda:print('No')
inf = 1 << 60
mod = 10 ** 9 + 7
mod = 998244353
eps = 1e-9
sortkey1 = itemgetter(0)
sortkey2 = lambda x: (x[0], x[1])
# sort(key=lambda x:(x[1], x[2]))


###############################################################

N, K = lp()
A = [-1 for _ in range(N)]
for _ in range(K):
    a, c = input().split()
    a = int(a) - 1
    A[a] = c
ans = []
RGB = 'RGB'
for i in range(N):
    if i % 3 == 0:
        s = 'R' if A[i] == -1 else A[i]
        ans.append(s)
    elif i % 3 == 1:
        s = 'R' if A[i] == -1 else A[i]
        if ans[-1] == s:
            for t in RGB:
                if t != s:
                    s = t
                    break
        ans.append(s)
    else:
        ss = ans[-1] + ans[-2]
        for t in RGB:
            if t not in ss:
                s = t
        ans.append(s)
print(''.join(ans))