n,k = map(int,input().split())
from collections import defaultdict
ac = defaultdict(str)
d = defaultdict(str)
for i in range(k):
    a,c = input().split()
    a = int(a)-1
    d[a] = c
rgb = ["R","G","B"]
ans = []
for i in range(-(-n//3)*3):
    ans.append(rgb[i%3])
for i in range(n):
    if (i % 3 == 2):continue
    if not d[i]:continue
    c = d[i]
    if i % 3 == 0:
        if ans[i] != c:
            idx = rgb.index(c)
            for j in range(3):
                ans[i+j] = rgb[(idx+j)%3] 
    if i % 3 == 1:
        if ans[i] != c and ans[i-1] != c: 
            ans[i],ans[i+1] = ans[i+1],ans[i]
print("".join(ans[:n]))