#include <bits/stdc++.h>
#define PB push_back
using namespace std;
const int N(20005);
int wlth[N], WLTH[N], dfn[N], low[N], visit[N], part[N], du[N];
int tot, partnum;
vector<int> eg[N], EG[N], egn[N], EGN[N];
stack<int> q;
void tarjan(int x)
{
    dfn[x] = low[x] = ++tot;
    q.push(x), visit[x] = 1;
    for (int i = 0; i < eg[x].size(); ++i)
    {
        if (!dfn[eg[x][i]])
        {
            tarjan(eg[x][i]);
            low[x] = min(low[x], low[eg[x][i]]);
        }
        else if (visit[eg[x][i]])
            low[x] = min(low[x], dfn[eg[x][i]]);
        // 注意一下low = min(low[x], low[eg[x][i]]); 有待思考
    }
    if (dfn[x] == low[x])
    {
        ++partnum;
        int y;
        do
        {
            y = q.top();
            q.pop();
            visit[y] = 0;
            part[y] = partnum;
            WLTH[partnum] += wlth[y];
        } while (y != x);
    }
}
int dis[N];
void topo()
{
    queue<int> q;
    for (int i = 1; i <= partnum; ++i)
        if (!du[i])
            q.push(i), dis[i] = 1;
    while (!q.empty())
    {
        int x = q.front();
        q.pop();
        for (int i = 0; i < EG[x].size(); ++i)
        {
            dis[EG[x][i]] = max(dis[EG[x][i]], dis[x] + EGN[x][i]);
            --du[EG[x][i]];
            if (!du[EG[x][i]])
                q.push(EG[x][i]);
        }
    }
    int ans = 0;
    for (int i = 1; i <= partnum; ++i)
        ans = max(ans, dis[i]);
    cout << ans;
}
map<string, int> mp;
int viss[N];
int tt;
int main()
{
    freopen("1.in", "r", stdin);
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; ++i)
    {
        string x, y;
        cin >> x >> y;
        if (!mp.count(x))
            mp[x] = ++tt;
        if (!mp.count(y))
            mp[y] = ++tt;
        eg[mp[x]].PB(mp[y]);
        egn[mp[x]].PB(0);
    }
    int tot = mp.size();
    for (int i = 1; i <= tt; ++i)
        if (!dfn[i])
            tarjan(i);
    for (int i = 1; i <= m; ++i)
    {
        string x, y;
        cin >> x >> y;
        if (!mp.count(x))
            mp[x] = ++tt;
        if (!mp.count(y))
            mp[y] = ++tt;
        if (!part[mp[x]])
            part[mp[x]] = ++partnum;
        if (!part[mp[y]])
            part[mp[y]] = ++partnum;
        eg[mp[x]].PB(mp[y]);
        egn[mp[x]].PB(1);
    }
    for (int i = 1; i <= tt; ++i)
        for (int j = 0; j < eg[i].size(); ++j)
            if (part[i] != part[eg[i][j]])
                EG[part[i]].PB(part[eg[i][j]]), du[part[eg[i][j]]]++,
                    EGN[part[i]].PB(egn[i][j]);
    topo();

    cout << " " << partnum << endl;
    return 0;
}

answer.code: In function ‘void tarjan(int)’:
answer.code:12:16: error: reference to ‘visit’ is ambiguous
   12 |     q.push(x), visit[x] = 1;
      |                ^~~~~
In file included from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:80,
                 from answer.code:1:
/usr/include/c++/13/variant:1827:5: note: candidates are: ‘template<class _Visitor, class ... _Variants> constexpr std::__detail::__variant::__visit_result_t<_Visitor, _Variants ...> std::visit(_Visitor&&, _Variants&& ...)’
 1827 |     visit(_Visitor&& __visitor, _Variants&&... __variants)
      |     ^~~~~
answer.code:5:39: note:                 ‘int visit [20005]’
    5 | int wlth[N], WLTH[N], dfn[N], low[N], visit[N], part[N], du[N];
      |                                       ^~~~~
answer.code:20:18: error: reference to ‘visit’ is ambiguous
   20 |         else if (visit[eg[x][i]])
      |                  ^~~~~
/usr/include/c++/13/variant:1827:5: note: candidates are: ‘template<class _Visitor, class ... _Variants> constexpr std::__detail::__variant::__visit_result_t<_Visitor, _Variants ...> std::visit(_Visitor&&, _Variants&& ...)’
 1827 |     visit(_Visitor&& __visitor, _Variants&&... __variants)
      |     ^~~~~
answer.code:5:39: note:                 ‘int visit [20005]’
    5 | int wlth[N], WLTH[N], dfn[N], low[N], visit[N], part[N], du[N];
      |                                       ^~~~~
answer.code:32:13: error: reference to ‘visit’ is ambiguous
   32 |             visit[y] = 0;
      |             ^~~~~
/usr/include/c++/13/variant:1827:5: note: candidates are: ‘template<class _Visitor, class ... _Variants> constexpr std::__detail::__variant::__visit_result_t<_Visitor, _Variants ...> std::visit(_Visitor&&, _Variants&& ...)’
 1827 |     visit(_Visitor&& __visitor, _Variants&&... __variants)
      |     ^~~~~
answer.code:5:39: note:                 ‘int visit [20005]’
    5 | int wlth[N], WLTH[N], dfn[N], low[N], visit[N], part[N], du[N];
      |                                       ^~~~~
answer.code: In function ‘int main()’:
answer.code:67:12: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   67 |     freopen("1.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~