被一道普及组的题卡了这么长时间，不开心。调了两三天，发现cnt=0;放错位置了。
至于原题，COGS
经（简）典（单）的拓扑排序，数据范围还这么小。。。

#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
#include <vector>
using namespace std;
queue <int> q;
int n, m, in[1005], b[1005],level;
bool map[1005][1005], a[1005];
inline int get_num()
{
	int ans = 0;
	char tmp;
	tmp = getchar();
	while (tmp > '9' || tmp < '0')	tmp = getchar();
	while (tmp <= '9'&&tmp >= '0')
	{
		ans = ans * 10 + tmp - 48;
		tmp = getchar();
	}
	return ans;
}
int main()
{
	freopen("level2013.in", "r", stdin);
	freopen("level2013.out", "w", stdout);
	int si, tmp, cnt;
	n = get_num();
	m = get_num();
	for (int i = 1; i <= m; i++)
	{
		cnt = 0;
		si = get_num();
		memset(a, 0, sizeof(a));
		for (int j = 1; j <= si; j++)
		{
			tmp = get_num();
			b[++cnt] = tmp;
			a[tmp] = true;
		}
		for (int j = b[1]; j <= b[cnt]; j++)
		{
			if (!a[j])
			{
				for (int k = 1; k <= cnt; k++)
				{
					if (!map[j][b[k]])
					{
						map[j][b[k]] = 1;
						in[b[k]]++;
					}
				}
			}
		}
	}
	for (int i = 1; i <= n; i++)
	{
		if (!in[i])
			q.push(i);
	}
	while (!q.empty())
	{
		si = q.size();
		level++;
		for (int i = 1; i <= si; i++)
		{
			int ti = q.front();
			q.pop();
			for (int j = 1; j <= n; j++)
			{
				if (map[ti][j])
				{
					in[j]--;
					if (!in[j])
						q.push(j);
				}
			}
		}
	}
	cout << level << "\n";
	return 0;
}