/* -*- coding: utf-8 -*-
 *
 * 3234.cc:  No.3234 Infinite Propagation - yukicoder
 */

#include<cstdio>
#include<algorithm>
#include<utility>

using namespace std;

/* constant */

const int MAX_L = 200000;
const int INF = 1 << 30;

/* typedef */

using pii = pair<int,int>;

/* global variables */

char s[MAX_L + 4];

/* subroutines */

pii read() {
  scanf("%s", s);
  int cs[2] = {};
  for (int i = 0; s[i]; i++) cs[s[i] - 'a']++;
  return {cs[0], cs[1]};
}

/* main */

int main() {
  int tn;
  scanf("%d", &tn);

  while (tn--) {
    int n;
    scanf("%d", &n);

    bool ok = false;
    int b0 = 0, b1 = INF, b2 = INF;
    for (int i = 0; i < n; i++) {
      auto [xa, xb] = read();
      auto [ya, yb] = read();
      if (xa == 1 && xb == 0) { // 'a'
	if (ya > 0) ok = true;
	else b0 = max(b0, yb);
      }
      else if (xa == 0 && xb > 0) { // 'bbb..'
	if (ya > 0) b1 = min(b1, xb);
	else b2 = min(b2, xb);
      }
    }
    //printf(" b0=%d,b1=%d,b2=%d\n", b0, b1, b2);

    if (b0 >= b2) b0 = INF;
    if (b0 >= b1) ok = true;

    if (ok) puts("Yes");
    else puts("No");
  }

  return 0;
}