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//~ while (clock()<=69*CLOCKS_PER_SEC)
//~ #pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("O3")
//~ #pragma GCC optimize("Ofast")
//~ #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//~ #pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;
using namespace std;

template <typename T>
using ordered_set =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define sim template < class c
#define ris return * this
#define dor > debug & operator <<
#define eni(x) sim > typename \
  enable_if<sizeof dud<c>(0) x 1, debug&>::type operator<<(c i) {
sim > struct rge { c b, e; };
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c* x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
~debug() { cerr << endl; }
eni(!=) cerr << boolalpha << i; ris; }
eni(==) ris << range(begin(i), end(i)); }
sim, class b dor(pair < b, c > d) {
  ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
  *this << "[";
  for (auto it = d.b; it != d.e; ++it)
    *this << ", " + 2 * (it == d.b) << *it;
  ris << "]";
}
#else
sim dor(const c&) { ris; }
#endif
};
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

#define shandom_ruffle random_shuffle

using ll=long long;
using pii=pair<int,int>;
using pll=pair<ll,ll>;
using vi=vector<int>;
using vll=vector<ll>;
const int nax=407;

int n, m, k;
vi graf[nax];

int blok[nax];
int dp[nax];

int nope[nax];

int wyn;

int licz()
{
	int ret=0;
	for (int i=n; i; i--)
	{
		dp[i]=0;
		if (blok[i])
			continue;
		for (int j : graf[i])
			dp[i]=max(dp[i], dp[j]);
		dp[i]++;
		ret=max(ret, dp[i]);
	}
	return ret;
}

vi sciezka()
{
	int w=licz();
	vi ret;
	for (int i=1; i<=n; i++)
	{
		if (dp[i]==w)
		{
			int v=i;
			ret.push_back(v);
			for (int j=w-1; j; j--)
			{
				for (int l : graf[v])
				{
					if (dp[l]==j)
					{
						v=l;
						break;
					}
				}
				ret.push_back(v);
			}
			break;
		}
	}
	return ret;
}

void rek(int v)
{
	if (!v)
	{
		wyn=min(wyn, licz());
		return;
	}
	vi wez=sciezka();
	for (int i : wez)
	{
		if (!nope[i])
		{
			blok[i]=1;
			rek(v-1);
			blok[i]=0;
		}
		nope[i]++;
	}
	for (int i : wez)
		nope[i]--;
}

int main()
{
	scanf("%d%d%d", &n, &m, &k);
	for (int i=1; i<=m; i++)
	{
		int a, b;
		scanf("%d%d", &a, &b);
		graf[a].push_back(b);
	}
	wyn=n;
	rek(k);
	printf("%d\n", wyn);
	return 0;
}