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#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;

#define FOR(i,a,n) for (auto i ## __ = (n), i = (a); i <= i ## __; ++i)
#define FORD(i,a,n) for (auto i ## __ = (n), i = (a); i >= i ## __; --i)
#define REP(i,n) FOR(i,0, n - 1)
#define REPD(i,n) FORD(i, n - 1, 0)
#define ALL(h) begin(h), end(h)
#define EB emplace_back
#define X first
#define Y second
#define V vector
#define SZ(x) (int)(x).size()
#define tpv typedef V<

typedef long long LL;
typedef pair<int, int> PII;
tpv int> VI;
tpv VI> VVI;
tpv PII> VPII;
tpv LL> VLL;

constexpr char nl = '\n';
#define endl nl
#define ris return *this
#define tem template<class t

tem, class u> inline void mini(t& a, u&& b) { if (b < a) a = b; }
tem, class u> inline void maxi(t& a, u&& b) { if (b > a) a = b; }
int ceil2(int h) { return h < 2 ? 1 : 1 << (sizeof(h) * 8 - __builtin_clz(h - 1)); }

tem> struct Dump { t a, b; };
tem> auto dump(t&& h) -> Dump<decltype(begin(h))> { return {ALL(h)}; }
tem> auto stub(t* h) -> decltype(cerr << *h, 0);
tem> char stub(...);
#define enif(o) tem> typename enable_if<sizeof stub<t>(0) o 1, debug&>::type operator<<(t h)
#define dor > debug& operator<<
struct debug {
#ifdef DEBUG
#define deb debug()
	~debug() { cerr << nl; }
	enif(!=) { cerr << boolalpha << h; ris; }
	enif(==) {
		*this << '{';
		for (auto a = begin(h), b = end(h); a != b;)
			*this << *a++ << &" "[a == b];
		ris << '}';
	}
	tem, class u dor(pair<t, u> p) { ris << '(' << p.X << ", " << p.Y << ')'; }
	tem dor(Dump<t> d) {
		*this << "{\n";
		for (t a = d.a, c = a; a != d.b; ++a)
			*this << "  " << distance(c, a) << ": " << *a << nl;
		ris << '}';
	}
#else
	operator int() { return 0; }
#define deb 0 and debug()
	tem dor(t&&) { ris; }
#endif
};

#define imie(h...) #h ": " << (h) << " "
#define LOG(h...) deb << imie(h)
#define DOG(h...) deb << #h ": " << dump(h) << " "

int n, m, k;
VVI v, vr;
V<bool> del;
VI order;

int rek(int level = 0) {
	// znajdz najdluzsza sciezke
	VI dp(n);
	VI best(n, -1);
	int mx_len = -1, mx_beg = -1;
	REPD (i, n) {
		int x = order[i];
		if (del[x])
			continue;
		for (auto& j : v[x]) {
			if (del[j])
				continue;
			if (dp[x] < dp[j] + 1) {
				dp[x] = dp[j] + 1;
				best[x] = j;
			}
		}
		if (dp[x] > mx_len) {
			mx_len = dp[x];
			mx_beg = x;
		}
	}
	VI path;
	int cur = mx_beg;
	while (cur != -1) {
		path.EB(cur);
		cur = best[cur];
	}
	
	// ostatni poziom
	if (level == k)
		return SZ(path);
	
	int ret = n - level;
	for (auto &i : path) {
		del[i] = true;
		ret = min(ret, rek(level + 1));
		del[i] = false;
	}
	
	return ret;
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	
	cin >> n >> m >> k;
	
	if (n <= k) {
		cout << 0 << endl;
		return 0;
	}
	
	del.resize(n);
	v.resize(n);
	VI in(n);
	REP (i, m) {
		int a, b;
		cin >> a >> b;
		a--; b--;
		v[a].EB(b);
		in[b]++;
	}
	
	REP (i, n)
		if (in[i] == 0)
			order.EB(i);
	
	for (int i = 0; i < SZ(order); i++) {
		int x = order[i];
		for (auto& j : v[x]) {
			in[j]--;
			if (in[j] == 0)
				order.EB(j);
		}
	}
	
	cout << rek() << endl;
	
	
	return 0;
}
/*
6 5 1
1 3
2 3
3 4
4 5
4 6

3 3 3
1 2
1 3
2 3
*/