n, k = map(int, input().split())
rgb = [""] * (n + 10)
for _ in range(k):
    a, c = input().split()
    rgb[int(a) - 1] = c

for i in range(0, n, 3):
    se = {"R", "G", "B"}
    se2 = set()
    for j in range(i, 3 + i):
        if rgb[j] in se:
            se.remove(rgb[j])
            se2.add(rgb[j])
    lst = sorted(se)
    for j in range(i, 3 + i):
        if rgb[j] == "":
            rgb[j] = lst.pop()
        elif rgb[j] in se2:
            se2.remove(rgb[j])
        else:
            rgb[j] = lst.pop()
print(*rgb[:n], sep="")