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#include <iostream>
#include <vector>
#include <bitset>
#include <queue>

const int MAXN = 305;
const int MAXM = 405;

int n,m,k;
std::vector<int> V[MAXN];
int deg[MAXN];
int K[MAXN];

int calcK(const std::bitset<MAXN> &disabled)
{
    int result = 0;

    for (int i=1;i<=n;++i) deg[i] = 0;
    for (int i=1;i<=n;++i) K[i] = 0;
    for (int i=1;i<=n;++i)
    {
        if (!disabled[i])
            for (int j : V[i])
                ++deg[j];
    }
    std::queue<int> q;
    for (int i=1;i<=n;++i)
        if (!disabled[i] && deg[i] == 0)
        {
            q.push(i);
            K[i] = 1;
            result = 1;
        }

    while (!q.empty())
    {
        int i = q.front();
        q.pop();
        for (int j : V[i])
            if (!disabled[j])
            {
                deg[j]--;
                K[j] = std::max(K[j], K[i]+1);
                result = std::max(result, K[j]);
                if (deg[j] == 0) q.push(j);
            }
    }

    return result;
}

int globalResult = 300;
void bruteForce(int d, int i, std::bitset<MAXN> set)
{
    if (d == k)
    {
        for (;i<=n;++i)
        {
            set[i] = true;
            globalResult = std::min(globalResult, calcK(set));
            set[i] = false;
        }
    }
    else if (d < k)
    {
        for (;i<=n;++i)
        {
            set[i] = true;
            bruteForce(d+1, i+1, set);
            set[i] = false;
        }
    }
}

int main()
{
    std::cin >> n >> m >> k;
    for (int i=1;i<=n;++i)
    {
        int a,b;
        std::cin >> a >> b;
        V[a].push_back(b);
    }

    globalResult = calcK(0);

    bruteForce(1, 1, 0);

    std::cout << globalResult << std::endl;

    return 0;
}