#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
using namespace std;const int MAX_V = 205;vector<int> G[MAX_V];  // 图
int V;                  // 顶点数
int color[MAX_V];       // 顶点i的颜色 1 或 -1// 把顶点染成1或-1
bool dfs(int v, int c)
{color[v] = c; // 把顶点v染成颜色cfor (int i = 0; i < G[v].size(); ++i) {if (color[G[v][i]] == c) return false;if (color[G[v][i]] == 0 && !dfs(G[v][i], -c)) return false;}return true;
}void solve()
{for (int i = 0; i < V; ++i) {if (color[i] == 0) {if (!dfs(i, 1)) {puts("No");return ;}}}puts("Yes");
}int main()
{int E;while (scanf("%d%d", &V, &E) == 2) {int a, b;for (int i = 0; i < V; ++i) G[i].clear();         memset(color, 0, sizeof color);for (int i = 0; i < E; ++i) {scanf("%d%d", &a, &b);G[a].push_back(b);G[b].push_back(a);}solve();}return 0;
}

#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
using namespace std;const int MAX_V = 105;
bool knows[MAX_V][MAX_V];vector<int> G[MAX_V];
int V;
int color[MAX_V];bool dfs(int v, int c)
{color[v] = c;for (unsigned i = 0; i < G[v].size(); ++i) {if (color[G[v][i]] == c) return false;if (color[G[v][i]] == 0 && !dfs(G[v][i], -c)) return false;}return true;
}void solve()
{for (int i = 1; i <= V; ++i) {if (color[i] == 0) {if (!dfs(i, 1)) {puts("NO");return ;}}}puts("YES");
}int main()
{while (~scanf("%d", &V)) {memset(knows, false, sizeof knows);for (int i = 0; i <= V; ++i) G[i].clear();memset(color, 0, sizeof color);int a;for (int i = 1; i <= V; ++i) {while (~scanf("%d", &a) && a)knows[i][a] = true;}for (int i = 1; i <= V; ++i) {for (int j = i + 1; j <= V; ++j) {if (!knows[i][j] || !knows[j][i]) {G[i].push_back(j);G[j].push_back(i);}}}solve();}return 0;
}