import sys
input = sys.stdin.readline

N,K=map(int,input().split())

D=dict()
for i in range(K):
    x,y=input().split()
    D[int(x)-1]=y
    
ANS=[""]*(N+10)

for i in range(0,N,3):
    LIST=[]
    if i in D:
        LIST.append(D[i])
    if i+1 in D:
        if D[i+1] in LIST:
            pass
        else:
            LIST.append(D[i+1])
    if i+2 in D:
        if D[i+2] in LIST:
            pass
        else:
            LIST.append(D[i+2])

    while len(LIST)<3:
        for k in ["R","G","B"]:
            if k in LIST:
                continue
            else:
                LIST.append(k)

    ANS[i]=LIST[0]
    ANS[i+1]=LIST[1]
    ANS[i+2]=LIST[2]    
  
print("".join(ANS[:N]))