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#include <bits/stdc++.h>
#define MP make_pair
#define PB push_back
#define int long long
#define st first
#define nd second
#define rd third
#define FOR(i, a, b) for(int i =(a); i <=(b); ++i)
#define RE(i, n) FOR(i, 1, n)
#define FORD(i, a, b) for(int i = (a); i >= (b); --i)
#define REP(i, n) for(int i = 0;i <(n); ++i)
#define VAR(v, i) __typeof(i) v=(i)
#define FORE(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
#define __builtin_ctz __builtin_ctzll
#define __builtin_clz __builtin_clzll
#define __builtin_popcount __builtin_popcountll
using namespace std;
template<typename TH> void _dbg(const char* sdbg, TH h) { cerr<<sdbg<<"="<<h<<"\n"; }
template<typename TH, typename... TA> void _dbg(const char* sdbg, TH h, TA... t) {
  while(*sdbg != ',') { cerr<<*sdbg++; } cerr<<"="<<h<<","; _dbg(sdbg+1, t...);
}
#ifdef LOCAL
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#define debugv(x) {{cerr <<#x <<" = "; FORE(itt, (x)) cerr <<*itt <<", "; cerr <<"\n"; }}
#else
#define debug(...) (__VA_ARGS__)
#define debugv(x)
#define cerr if(0)cout
#endif
#define next ____next
#define prev ____prev
#define left ____left
#define hash ____hash
typedef long long ll;
typedef long double LD;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<ll> VLL;
typedef vector<pair<int, int> > VPII;
typedef vector<pair<ll, ll> > VPLL;

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 T1, class T2>
ostream& operator<< (ostream &out, pair<T1, T2> pair) { return out << "(" << pair.first << ", " << pair.second << ")";}
template<class A, class B, class C> struct Triple { A first; B second; C third;
  bool operator<(const Triple& t) const { if (st != t.st) return st < t.st; if (nd != t.nd) return nd < t.nd; return rd < t.rd; } };
template<class T> void ResizeVec(T&, vector<int>) {}
template<class T> void ResizeVec(vector<T>& vec, vector<int> sz) {
  vec.resize(sz[0]); sz.erase(sz.begin()); if (sz.empty()) { return; }
  for (T& v : vec) { ResizeVec(v, sz); }
}
typedef Triple<int, int, int> TIII;
template<class A, class B, class C>
ostream& operator<< (ostream &out, Triple<A, B, C> t) { return out << "(" << t.st << ", " << t.nd << ", " << t.rd << ")"; }
template<class T> ostream& operator<<(ostream& out, vector<T> vec) { out<<"("; for (auto& v: vec) out<<v<<", "; return out<<")"; }
template<class T> ostream& operator<<(ostream& out, set<T> vec) { out<<"("; for (auto& v: vec) out<<v<<", "; return out<<")"; }
template<class L, class R> ostream& operator<<(ostream& out, map<L, R> vec) { out<<"("; for (auto& v: vec) out<<v<<", "; return out<<")"; }

VVI forw, backw;
const int N = 1e3 +5;
int is_forb[N];
int n, m;
VI GetLongest() {
  VI dp(n + 1);
  int ans = 0;
  RE (i, n) {
    if (is_forb[i]) { dp[i] = -10000; continue; }
    dp[i] = 1;
    for (auto prv : backw[i]) {
      maxi(dp[i], dp[prv] + 1);
    }
    maxi(ans, dp[i]);
  }
  int guy = 0;
  RE (i, n) {
    if (is_forb[i]) { continue; }
    if (dp[guy] < dp[i]) {
      guy = i;
    }
  }
  VI zioms{guy};
  while (1) {
    int found = 0;
    for (auto x : backw[guy]) {
      if (dp[x] == dp[guy] - 1) {
        zioms.PB(x);
        found = 1;
        guy = x;
        break;
      }
    }
    if (!found) {
      return zioms;
    }
  }
  
//   int cnt_on_best = 0;
//   FORD (i, n, 1) {
//     maxi(dp_forw[i], 1ll);
//     for (auto nxt : forw[i]) {
//       maxi(dp_forw[i], dp_forw[nxt] + 1);
//     }
//     if (dp_forw[i] + dp_backw[i] == ans + 1) {
//       cnt_on_best++;
//     }
//   }
//   debug(cnt_on_best, ans);
}

int Solve(int rem) {
  VI longest = GetLongest();
  debug(longest);
  if (rem == 0) {
    return SZ(longest);
  }
  int ans = n;
  for (auto x : longest) {
    is_forb[x] = 1;
    mini(ans, Solve(rem - 1));
    is_forb[x] = 0;
  }
  return ans;
}

int32_t main() {

  ios_base::sync_with_stdio(0);
  cout << fixed << setprecision(10);
  cerr << fixed << setprecision(10);
  cin.tie(0);
  //double beg_clock = 1.0 * clock() / CLOCKS_PER_SEC;
  int k;
  //srand(clock());
  cin>>n>>m>>k;
  //forw.resize(n + 2);
  backw.resize(n + 2);
  if (n == k) { cout<<"0\n"; return 0; }
  RE (i, m) {
    int x, y;
    cin>>x>>y;
    //forw[x].PB(y);
    backw[y].PB(x);
  }
  cout<<Solve(k)<<endl;
  
  
  
  

  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  return 0;
}