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#include <algorithm>
#include <cstdio>
#include <vector>
using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define FORD(i,a,b) for(int i=(b)-1;i>=(a);--i)
#define REP(i,n) FOR(i,0,n)
#define REPD(i,n) FORD(i,0,n)
#define VAR(v,w) __typeof(w) v=(w)
#define FORE(it,c) for(VAR(it,(c).begin());it!=(c).end();++it)
#define PB push_back
#define INT(x) int x; scanf("%d", &x)

typedef vector<int> VI;

bool p[300];
VI g[300];
int h[300];

int main() {
	INT(n);
	INT(m);
	INT(k);
	REP(x,m) {
		INT(a);
		INT(b);
		g[a - 1].PB(b - 1);
	}
	FOR(i,n-k,n) p[i] = 1;
	int res = n;
	do {
		int r = 0;
		REPD(i,n) {
			h[i] = 0;
			if (p[i]) continue;
			FORE(it,g[i]) h[i] = max(h[i], h[*it]);
			++h[i];
			r = max(r, h[i]);
		}
		res = min(res, r);
	} while (next_permutation(p, p + n));
	printf("%d\n", res);
}