#include<cstdio>#include<cstring>using namespace std;#define P 110#define N 310int map[P][N];int match[N];bool use[N];int p, n;bool find(int u) //u是课程{for(int i = 1; i <= n; ++i){if(!use[i] && map[u][i]) //标记匹配的学生{use[i] = true;if(match[i] == - 1 || find(match[i])){match[i] = u;return true;}}}return false;}int sum(){int sumall = 0;for(int i = 1; i <= p; ++i) //统计匹配的课程{memset(use, false, sizeof(use));if(find(i))sumall++;}return sumall;}int main(){int ncase;int stunum, temp, ans;scanf("%d", &ncase);while(ncase--){memset(map, 0, sizeof(map));memset(match, -1, sizeof(match));scanf("%d%d", &p, &n);for(int i = 1; i <= p; ++i){scanf("%d", &stunum);for(int j = 1; j <= stunum; ++j){scanf("%d", &temp); map[i][temp] = 1; //j号学生喜欢i号课程}}ans = sum();printf("%sn", ans == p ? "YES" : "NO");}return 0;}
