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#include <bits/stdc++.h>
using namespace std;
#define e1 first
#define e2 second
#define pb push_back
#define mp make_pair
#define boost ios_base::sync_with_stdio(false)
#define eb emplace_back
#define OUT(x) {cout << x; exit(0); }
#define FOR(i, a, b) for (int i=(a); i<=(b); ++i)
typedef long long ll;
typedef unsigned long long ull;
typedef pair <int, int> PII;
typedef pair <ll, ll> PLL;
typedef pair <PLL, PLL> PP;
typedef unsigned int ui;
const int mod = 1e9+7;
const int inf = 1e9+9;
const ll MOD = 1e9+696969;
const ll INF = 1e18;

const int maxn = 305;
vector <int> rev[maxn], v[maxn];
bool mark[maxn];
int dpP[maxn], accP[maxn], dpS[maxn], accS[maxn], ost[maxn], n, m, k;
const int R = 512;
int dr[2 * R + 5], result;

inline void query(int x, int y, int val) {
	x += R-1; y += R-1;
	dr[x] = max(dr[x], val);
	dr[y] = max(dr[y], val);
	while (x + 1 < y) {
		if (!(x & 1)) dr[x + 1] = (dr[x + 1] >= val)?dr[x + 1] : val;
		if (y & 1) dr[y - 1] = (dr[y - 1] >= val)?dr[y - 1] : val;
		x >>= 1; y >>= 1;
	}
}
int CHE;

int solve() { //mark has to be properly set
	fill(dr, dr+R+R+2, 0);
	dpP[0] = accP[0] = 0;
	FOR(i, 1, n) {
		if (mark[i]) {
			accP[i] = accP[i-1];
			continue;
		}
		
		int step = 0;
		for (auto u : rev[i]) step = (!mark[u]&&dpP[u]>step)?dpP[u]: step;
		++step;
		dpP[i] = step;
		accP[i] = (accP[i-1] >= step)?accP[i-1]:step;
	}
	
	dpS[n + 1] = accS[n + 1] = 0;
	for (int i=n; i>0; --i) {
		if (mark[i]) {
			accS[i] = accS[i+1];
			continue;
		}
		int step = 0;
		for (auto u : v[i]) step = (!mark[u]&&dpS[u]>step)?dpS[u]:step;
		++step;
		dpS[i] = step;
		accS[i] = (accS[i+1] >= step)?accS[i+1]:step;
	}

	FOR(i, 1, n) {
		if (mark[i]) continue;
		for (auto u: v[i]) {
			if (!mark[u] && i+2 <= u) query(i+1, u-1, dpP[i]+dpS[u]);
		}
	}
	
	for (int i=1; i<R; ++i) {
		dr[i << 1] = (dr[i << 1] >= dr[i])?dr[i << 1] : dr[i];
		dr[i << 1 | 1] = (dr[i << 1 | 1] >= dr[i])?dr[i << 1 | 1] : dr[i];
	}
	
	int ret = n + 1;
	FOR(i, 1, n) {
		if (mark[i]) continue;
		ret = min(ret, max(accP[i - 1], max(accS[i + 1], dr[i + R - 1])));
	}
	
	return ret;
}

inline int solver(int m1, int m2, int m3) {
	mark[m1] = mark[m2] = mark[m3] = true;
	int w = solve();
	mark[m1] = mark[m2] = mark[m3] = false;
	return w;
}

vector <int> longestPath() {
	vector <int> ret;
	int bet = 0, opt = 0;
	FOR(i, 1, n) {
		if (mark[i]) continue;		
		int step = 0, os = 0;
		for (auto u : rev[i]) 
		if (!mark[u] && dpP[u] > step) {
			step = dpP[u];
			os = u;
		}	
		++step;
		dpP[i] = step;
		ost[i] = os;
		
		if (step > opt) {
			bet = i;
			opt = step;
		}
	}
	
	while (bet) {
		ret.pb(bet);
		bet = ost[bet];
	}
	
	return ret;
}

void backtrack(int level) {
	if (level == 1) {
		result = min(result, solve());
		return;
	}
	
	vector <int> longboi = longestPath();
	
	int sz = longboi.size();
	for (int i=0; i<sz; ++i) {
		int u = longboi[i];
		mark[u] = true;
		backtrack(level - 1);
		mark[u] = false;
	}
}

int main()
{
	boost;
	cin >> n >> m >> k;
	if (k == n) OUT(0);
	result = n + 1;
	
	FOR(i, 1, m) {
		int a, b;
		cin >> a >> b;
		v[a].pb(b);
		rev[b].pb(a);
	}
	
	if (k == 0) {
		solver(0, 0, 0);
		OUT(accP[n]);
	}
	
	backtrack(k);
	cout << result;
}