n,k = map(int,input().split())
ans = []
RGB = [0]*3

AC = []
for i in range(k):
    a,c = input().split()
    a = int(a)
    AC.append([a,c])
AC.sort()
l = "RGB"
now = 0
for i in range(1,n+1):
    if now < k and AC[now][0] == i:
        # print(i)
        c = AC[now][1]
        
        now += 1
        ind = l.index(c)
        # print(c,ind,RGB)
        if max(RGB) == RGB[ind]:
            if i%3 == 1:
                RGB[ind] += 1
                ans.append(ind)
            else:
                m = max(RGB)
                for j in range(3):
                    if RGB[j] != m:
                        RGB[j] += 1
                        ans.append(j)
                        break
        else:
            RGB[ind] += 1
            ans.append(j)
    else:
        if i%3 == 1:
            RGB[0] += 1
            ans.append(0)
        else:
            m = max(RGB)
            for j in range(3):
                if RGB[j] != m:
                    RGB[j] += 1
                    ans.append(j)

ans = [l[i] for i in ans]
print("".join(ans))