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

vector<vector<int>> v(301);

int best(vector<vector<int>>& v, vector<int>& deg, vector<int>& dist, vector<int>& from, int n){
	queue<int> q;
	for(int i = 1; i <= n; i++){
		if(deg[i] == 0){
			from[i] = -1;
			q.push(i);
		}
	}
	int best = 0;
	while(!q.empty()){
		int f = q.front();
		q.pop();
		for(int x: v[f]){
			if(dist[x] < dist[f] + 1){
				dist[x] = dist[f] + 1;
				from[x] = f;
			}
			if(dist[x] > dist[best]){
				best = x;
			}
			deg[x]--;
			if(deg[x] == 0){
				q.push(x);
			}
		}
	}
	return best;
}

vector<int> get_path(vector<int>& from, int start){
	vector<int> result;
	while(start != -1){
		result.push_back(start);
		start = from[start];
	}
	return result;
}
//int cnt = 0;
int result(vector<vector<int>>& v, int n, int k){
/*	cnt++;
	if(cnt % 1000 == 0){
		cout<<cnt<<endl;
	}*/
	vector<int> deg(n+1, 0), dist(n+1, 0), from(n+1);
	for(int i = 1; i <= n; i++){
		for(int x : v[i]){
			deg[x]++;
		}
	}
	int b = best(v, deg, dist, from, n);
	if(b == 0){
		return 1;
	}
	if(k == 0){
		return(dist[b] + 1);
	}
	vector<int> path = get_path(from, b);

	int res = 500;
	for(int i = 0; i < path.size(); i++){
		int x = path[i];
		//cout<<k<<" "<<x<<endl;
		vector<vector<int>> v_temp(n+1);
		for(int i = 1; i <= n; i++){
			if(i != x){
				for(int j = 0; j < (int)v[i].size(); j++){
					if(v[i][j] != x){
						v_temp[i].push_back(v[i][j]);
					}
				}
			}
		}
		res = min(res, result(v_temp, n, k-1));
	}
	return res;
}

int main(){
	int n, m, k;
	cin>>n>>m>>k;
	for(int i = 0; i < m; i++){
		int x, y;
		cin>>x>>y;
		v[x].push_back(y);
	}
	if(n == k){
		cout<<0<<endl;
		return 0;
	}
	cout<<result(v, n, k)<<endl;
}