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#include <bits/stdc++.h>
using namespace std;

const int N = 305;
int n, m, k, dp[N], gdz[N];
vector<int> adj[N], topo;
bool vis[N], block[N];

void dfs(int v)
{
  vis[v] = 1;
  for (auto u: adj[v])
    if (!vis[u])
      dfs(u);
  topo.push_back(v);
}

int licz()
{
  for (int i = n-1; i >= 0; i--)
  {
    int v = topo[i];
    dp[v] = 1; gdz[v] = -1;
    for (auto u: adj[v]) if (!block[u])
      if (dp[v] < dp[u] + 1)
      {
        dp[v] = dp[u] + 1;
        gdz[v] = u;
      }
  }
  int res = 0;
  for (auto v: topo) if (!block[v])
    res = max(res, dp[v]);
  return res;
}

int rek(int l)
{
  int x = licz();
  if (l == 0) return x;

  vector<int> path;
  int st = -1;
  for (auto v: topo)
    if (dp[v] == x && !block[v])
      st = v;
  while (st != -1)
  {
    path.push_back(st);
    st = gdz[st];
  }

  int result = n+1;
  for (auto v: path)
  {
    block[v] = 1;
    result = min(result, rek(l-1));
    block[v] = 0;
  }
  return result;
}

int main()
{
  scanf("%d%d%d", &n, &m, &k);
  for (int i = 0; i < m; i++)
  {
    int u, v; scanf("%d%d", &u, &v);
    adj[u].push_back(v);
  }

  for (int i = 1; i <= n; i++)
    if (!vis[i])
      dfs(i);

  reverse(topo.begin(), topo.end());

  printf("%d\n", rek(k));

  return 0;
}