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#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i=(a); (i)<(b); (i)++)
#define PPC(x) __builtin_popcountll((x))
#define ALL(x) (x).begin(), (x).end()
#define pb push_back
using namespace std;

const int maxN = 303;

inline void remin(int& a, int b)	{   a = min(a, b);  }
inline void remax(int& a, int b)	{   a = max(a, b);  }

struct MySet
{
	int cnt[maxN], st, ad, mx;
	long long T[5];
	
	void init()
	{
		cnt[0] = 1;
		T[0] = 1LL;
		st = 6, ad = 63, mx = 0;
	}
	
	void add(int v)
	{
		cnt[v]++;
		if (cnt[v] == 1)
		{
			int i = v >> st, j = v & ad;
			T[i] |= 1LL << j;
			remax(mx, v);
		}
	}
	
	void ers(int v)
	{
		cnt[v]--;
		if (cnt[v] == 0)
		{
			int i = v >> st, j = v & ad;
			T[i] ^= 1LL << j;
		}
	}
	
	void updt()
	{
		if (cnt[mx] == 0)
			for (int i=(mx>>st); i>=0; i--)
				if (T[i] != 0)
				{
					mx = (i+1) * 64 - 1 - __builtin_clzll(T[i]);
					break;
				}
	}
} Set;

vector <int> G[maxN], H[maxN];
bool erased[maxN];
int n, in[maxN], pref[maxN], out[maxN], suf[maxN], dp[maxN], dmn[3][maxN], res = maxN;

int myk()
{
	FOR(v, 1, n+1)
	{
		in[v] = 0;
		for (int u : H[v]) if(!erased[u])
			remax(in[v], in[u]);
		in[v]++;
		pref[v] = (pref[v - 1] < in[v] and !erased[v]) ? in[v] : pref[v - 1];
	}
	
	for (int v=n; v>=1; v--)
	{
		out[v] = 0;
		for (int u : G[v]) if(!erased[u])
			remax(out[v], out[u]);
		out[v]++;
		suf[v] = (suf[v + 1] < out[v] and !erased[v]) ? out[v] : suf[v + 1];
	}
	
	int ret = n;
	FOR(v, 1, n+1)
	{
		if (erased[v])
			continue;
		for (int u : H[v])	if(!erased[u])
			Set.ers(in[u] + out[v]);
		Set.updt();
		int hisret = max({pref[v - 1], suf[v + 1], Set.mx});		
		remin(ret, hisret);
		for (int u : G[v])	if(!erased[u])
			Set.add(in[v] + out[u]);
	}
	return ret;
}

int filldmn(int* d)
{
	int maxlen = 0;
	for (int v=n; v>=1; v--)
	{
		dp[v] = 0;
		if (erased[v])
			continue;
		for (int u : G[v])
			if (!erased[u])
				remax(dp[v], dp[u]);
		remax(maxlen, ++dp[v]);
	}
	int v = 1, s = 0;
	while (dp[v] != maxlen)	v++;
	while (dp[v] != 1)
	{
		d[s++] = v;
		for (int u : G[v])
			if (!erased[u] and dp[u] == dp[v] - 1)
			{	v = u;	break;	}
	}
	d[s++] = v;
	return s;
}
 
void go(int depth)
{
	if (depth == -1)
	{	remin(res, myk()); return;	}
	
	int *d = dmn[depth], s = filldmn(d);
	FOR(i, 0, s)
	{
		erased[d[i]] = true;
		go(depth - 1);
		erased[d[i]] = false;
	}
}

void ext(int ans)
{
	printf("%d\n", ans);
	exit(0);
}

int main()
{
	int m, k;
	scanf ("%d%d%d", &n, &m, &k);
	while (m--)
	{
		int a, b;
		scanf ("%d%d", &a, &b);
		G[a].pb(b);
		H[b].pb(a);
	}
	Set.init();
	if (k == n)
		ext(0);
	if (k == 0)
		ext(filldmn(dmn[0]));
	go(k-2);
	printf("%d\n", res);
	return 0;
}