#include #include #include #define x first #define y second

using namespace std; typedef pair<int, int> PII;

const int N = 1005; int T; int g[N][N]; int dist[N][N]; PII q[N * N];

int dx[] = {-1, 0, 1, 0}, dy[] = {0, 1, 0, -1};

bool bfs(int x1, int y1, int n){ int hh = 0, tt = 0; dist[x1][y1] = 0; q[tt++] = {x1, y1}; while(hh <= tt){ PII t = q[hh++]; for(int i = 0; i<4; i++){ int a = t.x + dx[i], b = t.y + dy[i]; if(a < 1 || a > n || b < 1 || b > n) continue; if(dist[a][b] != -1) continue; if(dist[t.x][t.y] + 1 > g[a][b]) continue; q[tt++] = {a, b}; dist[a][b] = dist[t.x][t.y] + 1; if(a == n && b == n) return true; } } return false; }

int main(){ scanf("%d", &T); while(T--){ memset(g, 0x3f, sizeof g); memset(dist, -1 , sizeof dist); int n; scanf("%d",&n); if(n == 1){ printf("YES\n"); continue; } for(int i = 1; i<= 2*n - 2; i++){ int x1, y1; scanf("%d %d",&x1, &y1); g[x1][y1] = min(g[x1][y1], i); } if(bfs(1,1,n)) printf("YES\n"); else printf("NO\n"); } return 0; }