package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)
var out = bufio.NewWriter(os.Stdout)

func main() {
	buf := make([]byte, 1024*1024)
	sc.Buffer(buf, bufio.MaxScanTokenSize)
	sc.Split(bufio.ScanWords)

	t := nextInt()
	var ans []string
	for i := 0; i < t; i++ {
		n := nextInt()
		var c []string
		var d []int
		for i := 0; i < n; i++ {
			c = append(c, nextString())
			d = append(d, nextInt()-1)
		}
		ans = append(ans, solve(n, c, d))
	}
	PrintVertically(ans)
}

func solve(n int, c []string, d []int) string {
	m := map[string]int{"R": 2 * n, "G": 2*n + 1, "B": 2*n + 2}
	uf := NewUnionFind(2*n + 3)
	for i := 0; i < n; i++ {
		uf.Unite(i, m[c[i]])
		uf.Unite(i, n+d[i])
	}
	//PrintUnionFind(uf)
	ok := true
	root := uf.Find(0)
	for i := 0; i < n; i++ {
		ok = ok && root == uf.Find(i)
	}
	if ok {
		return "YES"
	} else {
		return "NO"
	}
}

type UnionFind struct {
	parent []int // parentent numbers
	rank   []int // height of tree
	size   []int
}

func New(n int) *UnionFind {
	return NewUnionFind(n)
}

func NewUnionFind(n int) *UnionFind {
	if n <= 0 {
		return nil
	}
	u := new(UnionFind)
	// for accessing index without minus 1
	u.parent = make([]int, n+1)
	u.rank = make([]int, n+1)
	u.size = make([]int, n+1)
	for i := 0; i <= n; i++ {
		u.parent[i] = i
		u.rank[i] = 0
		u.size[i] = 1
	}
	return u
}

func (uf *UnionFind) Find(x int) int {
	if uf.parent[x] == x {
		return x
	} else {
		// compress path
		// ex. Find(4)
		// 1 - 2 - 3 - 4
		// 1 - 2
		//  L-3
		//  L 4
		uf.parent[x] = uf.Find(uf.parent[x])
		return uf.parent[x]
	}
}

func (uf *UnionFind) Size(x int) int {
	return uf.size[uf.Find(x)]
}

func (uf *UnionFind) ExistSameUnion(x, y int) bool {
	return uf.Find(x) == uf.Find(y)
}

func (uf *UnionFind) Unite(x, y int) {
	x = uf.Find(x)
	y = uf.Find(y)
	if x == y {
		return
	}
	// rank
	if uf.rank[x] < uf.rank[y] {
		//yがrootの木にxがrootの木を結合する
		uf.parent[x] = y
		uf.size[y] += uf.size[x]
	} else {
		// uf.rank[x] >= uf.rank[y]
		//xがrootの木にyがrootの木を結合する
		uf.parent[y] = x
		uf.size[x] += uf.size[y]
		if uf.rank[x] == uf.rank[y] {
			uf.rank[x]++
		}
	}
}

func PrintUnionFind(u *UnionFind) {
	// for debuging. not optimize.
	fmt.Println(u.parent)
	fmt.Println(u.rank)
	fmt.Println(u.size)
}

func nextInt() int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return i
}

func nextString() string {
	sc.Scan()
	return sc.Text()
}

func PrintVertically(x []string) {
	defer out.Flush()
	for _, v := range x {
		fmt.Fprintln(out, v)
	}
}