import bisect
import copy
import decimal
import fractions
import heapq
import itertools
import math
import random
import sys
import time
from collections import Counter,deque,defaultdict
from functools import lru_cache,reduce
from heapq import heappush,heappop,heapify,heappushpop,_heappop_max,_heapify_max
def _heappush_max(heap,item):
    heap.append(item)
    heapq._siftdown_max(heap, 0, len(heap)-1)
def _heappushpop_max(heap, item):
    if heap and item < heap[0]:
        item, heap[0] = heap[0], item
        heapq._siftup_max(heap, 0)
    return item
from math import gcd as GCD
read=sys.stdin.read
readline=sys.stdin.readline
readlines=sys.stdin.readlines
write=sys.stdout.write

N,K=map(int,readline().split())
C=[None]*N
for k in range(K):
    A,c=readline().split()
    A=int(A)-1
    C[A]=c
ans_lst=[None]*N
cnt={s:0 for s in "RGB"}
for n in range(N):
    if C[n]!=None and (max(cnt.values())>cnt[C[n]] or min(cnt.values())==cnt[C[n]]):
        cnt[C[n]]+=1
        ans_lst[n]=C[n]
    else:
        for s in "RGB":
            if min(cnt.values())==cnt[s]:
                cnt[s]+=1
                ans_lst[n]=s
                break
print(*ans_lst,sep="")