n, k = map(int, input().split())
AC = [list(input().split()) for _ in range(k)]
C = ['R' for _ in range(n)]
for i in range(k):
    idx, c = AC[i]
    idx = int(idx) - 1
    C[idx] = c

j = 0
ANS = ['R' for _ in range(n)]
for i in range(n):
    c = C[i]
    if i % 3 == 1:
        if ANS[i - 1] == c:
            if c == 'R':
                c = 'G'
            else:
                c = 'R'
    elif i % 3 == 2:
        L = set(['R', 'G', 'B'])
        L.remove(ANS[i - 2])
        L.remove(ANS[i - 1])
        c = list(L)[0]
    ANS[i] = c
print(''.join(ANS))