import sys
input = sys.stdin.readline
from collections import *

class Unionfind:
    def __init__(self, n):
        self.par = [-1]*n
        self.rank = [1]*n
    
    def root(self, x):
        r = x
        
        while not self.par[r]<0:
            r = self.par[r]
        
        t = x
        
        while t!=r:
            tmp = t
            t = self.par[t]
            self.par[tmp] = r
        
        return r
    
    def unite(self, x, y):
        rx = self.root(x)
        ry = self.root(y)
        
        if rx==ry:
            return
        
        if self.rank[rx]<=self.rank[ry]:
            self.par[ry] += self.par[rx]
            self.par[rx] = ry
            
            if self.rank[rx]==self.rank[ry]:
                self.rank[ry] += 1
        else:
            self.par[rx] += self.par[ry]
            self.par[ry] = rx
    
    def is_same(self, x, y):
        return self.root(x)==self.root(y)
    
    def count(self, x):
        return -self.par[self.root(x)]

def f(c):
    if c=='R':
        return 0
    elif c=='G':
        return 1
    else:
        return 2

def solve():
    N = int(input())
    CD = []
    uf = Unionfind(N+3)
    
    for _ in range(N):
        C, D = input().split()
        D = int(D)
        CD.append((C, D))
        uf.unite(f(C), 2+D)
    
    cnt = [0]*(N+3)
    
    for C, D in CD:
        cnt[uf.root(f(C))] += 1
    
    if max(cnt)==N:
        print('YES')
    else:
        print('NO')

for _ in range(int(input())):
    solve()