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//ciekawe jak szybko takie cos dziala

#pragma GCC optimize("O3")
#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// using namespace __gnu_pbds;
// gp_hash_table<int, int> mapka;

using namespace std;
#define PB push_back
#define MP make_pair
#define LL long long
#define int LL
#define FOR(i,a,b) for(int i = (a); i <= (b); i++)
#define RE(i,n) FOR(i,1,n)
#define REP(i,n) FOR(i,0,(int)(n)-1)
#define R(i,n) REP(i,n)
#define VI vector<int>
#define PII pair<int,int>
#define LD long double
#define FI first
#define SE second
#define st FI
#define nd SE
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())

template<class C> void mini(C &a4, C b4) { a4 = min(a4, b4); }
template<class C> void maxi(C &a4, C b4) { a4 = max(a4, b4); }

template<class TH> void _dbg(const char *sdbg, TH h){ cerr<<sdbg<<'='<<h<<endl; }
template<class TH, class... TA> void _dbg(const char *sdbg, TH h, TA... a) {
  while(*sdbg!=',')cerr<<*sdbg++;
  cerr<<'='<<h<<','; _dbg(sdbg+1, a...);
}

template<class T> ostream &operator<<(ostream& os, vector<T> V) {
  os << "["; for (auto vv : V) os << vv << ","; return os << "]";
}
template<class L, class R> ostream &operator<<(ostream &os, pair<L,R> P) {
  return os << "(" << P.st << "," << P.nd << ")";
}

#ifdef LOCAL
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) (__VA_ARGS__)
#define cerr if(0)cout
#endif

const int MAX = 301;
vector<int> d[MAX];
int cz[MAX];
int n,m;
int us(int k){
  vector<int> res(n);
  vector<int> pop(n, -1);
  int kt = -1;
  R(i,n)if(cz[i] != 1){
    res[i] = 1;
    for(int el:d[i])if(cz[el] != 1){
      if(res[i] < res[el] + 1){
        res[i] = res[el] + 1;
        pop[i] = el;
      }
    }
    if(kt == -1 || res[i] > res[kt]){
      kt = i;
    }
  }
  
  if(k == 0)return res[kt];
  
  vector<int> sc;
  while(kt != -1){
    sc.PB(kt);
    kt = pop[kt];
  }
  debug(sc);
  int wyn = 1e9;
  vector<int> pamcz(SZ(sc));
  R(i,SZ(sc))pamcz[i] = cz[sc[i]];
  R(i,SZ(sc)){
    int pom = sc[i];
    if(cz[pom] == 0){
      cz[pom] = 1;
      mini(wyn, us(k-1));
      cz[pom] = 2;
    }
  }
  R(i,SZ(sc))cz[sc[i]] = pamcz[i];
  return wyn;
}

int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout << fixed << setprecision(11);
  cerr << fixed << setprecision(6);
  int k;
  cin >> n >> m >> k;
  if(n == k){
    cout << "0\n";
    return 0;
  }
  R(i,m){
    int a,b;
    cin >> a >> b;
    a--;b--;
    d[b].PB(a);
  }
  cout << us(k) << "\n";
}