import collections
N,K = map(int, input().split())
AC = [list(input().split()) for _ in range(K)]
AC = sorted(AC, reverse=True, key=lambda x: x[1])
THREE = collections.defaultdict(list)
for a,c in AC:
    THREE[(int(a)-1)//3].append(c)
HAT = []
for i in range(N//3+1):
    USE = {'R','G','B'}
    for c in THREE[i]:
        if c in USE:
            HAT.append(c)
        USE.discard(c)
    HAT.extend(list(USE))
print(''.join(map(str, HAT[:N])))