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#include <iostream>
#include <vector>
using namespace std;

const int N = 301;
const int M = 401;

int n, m, k;
bool used[N];
int longest[N];
int q[N];
int best;
vector<int> G[N];

vector<int> updateLongest() {
    int cur = 0;
    for (int i = n; i > 0; --i) {
        if (used[i]) {
            longest[i] = -2;
            continue;
        }
        longest[i] = 0;
        q[i] = -1;
        for (int j = 0; j < G[i].size(); ++j) {
            if (!used[G[i][j]] && longest[G[i][j]] + 1 > longest[i]) {
                longest[i] = longest[G[i][j]] + 1;
                q[i] = G[i][j];
                if (longest[i] > longest[cur]) cur = i;
            }
        }
    }
    vector<int> nodes;
    while (cur != -1) {
        nodes.push_back(cur);
        cur = q[cur];
    }
    return nodes;
}

void qq(int left) {
    vector<int> nodes = updateLongest();
    if (left == 0) {
        if (best > nodes.size()) best = nodes.size();
        return;
    }
    for (int i = 0; i < nodes.size(); ++i) {
        used[nodes[i]] = true;
        qq(left - 1);
        used[nodes[i]] = false;
    }
}

int main() {
    int a, b;
    best = 400;
    cin>>n>>m>>k;
    if (k >= n) {
        cout<<0<<endl;
        return 0;
    }
    for (int i = 0; i < m; ++i) {
        cin>>a>>b;
        G[a].push_back(b);
    }
    qq(k);
    cout<<best<<endl;
    return 0;
}