import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################
n, k = na()
r,g,b = 0,0,0
def f(x):return int(x[0]),x[1]
d = [None]*((n+2)//3*3)
for i in range(k):
    a,c = f(input().split())
    d[a-1] = c

ans = [None]*((n+2)//3*3)
for i in range((2+n)//3):
    x,y,z = None,None,None

    x = d[i*3]
    if x == None:
        x = "G"
    if d[i*3+1] != None and d[i * 3 + 1] != x:
        y = d[i*3 + 1]
    elif x == "G":
        y = "B"
    else:
        y = "G"
    p = ["R","G","B"]
    p.remove(x)
    p.remove(y)
    z = p[0]
    ans[i*3],ans[i*3+1],ans[i*3+2] = x,y,z
print("".join(ans[:n]))