n,k=map(int,input().split())
q=["R"]*n
for i in range(k):
  a,c=input().split()
  a=int(a)-1
  q[a]=c
a=["."]*n
for i in range(0,n,3):
  for j in range(3):
    if i+j<n:
      for c in "RGB":
        if j==0:
          if c==q[i+j]:
            a[i+j]=c
        if j==1:
          if c!=a[i+j-1] and (c==q[i+j] or q[i+j-1]==q[i+j]):
            a[i+j]=c
        if j==2:
          if c!=a[i+j-2] and c!=a[i+j-1]:
            a[i+j]=c
print("".join(a))