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#include <bits/stdc++.h>

using namespace std;

const int N = 305;

int n, m, k, a, b;
vector<int> V[N];
bool removed[N];
int dp[N], nxt[N];
int ans;
int start;

int solve() {
    int ret = 0;
    for (int i = n; i >= 1; i--) {
        if (removed[i]) continue;
        dp[i] = 1;
        nxt[i] = n + 1;
        for (int u : V[i]) {
            if (removed[u]) {
                continue;
            }
            dp[i] = max(dp[i], dp[u] + 1);
            if (dp[i] == dp[u] + 1) {
                nxt[i] = u;
            }
        }
        ret = max(ret, dp[i]);
        if (dp[i] == ret) {
            start = i;
        }
    }
    return ret;
}

void backtrack(int r) {
    if (r == 0) {
        ans = min(ans, solve());
        return;
    }
    solve();
    int w = start;
    vector<int> path;
    while (w != n + 1) {
        path.push_back(w);
        w = nxt[w];
    }
    for (int w : path) {
        removed[w] = true;
        backtrack(r - 1);
        removed[w] = false;
    }
}

int main() {
    
    scanf("%d %d %d", &n, &m, &k);
    
    for (int i = 1; i <= m; i++) {
        scanf("%d %d", &a, &b);
        V[a].push_back(b);
    }
    
    ans = solve();
    backtrack(k);

    printf("%d\n", ans);
    
    return 0;
}