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#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <set>
#include <map>
#include <cstdio>
#include <sstream>
#include <iostream>
#include <cstring>
#define REP(i,x,v)for(int i=x;i<=v;i++)
#define REPD(i,x,v)for(int i=x;i>=v;i--)
#define FOR(i,v)for(int i=0;i<v;i++)
#define FOREACH(i,t) for (typeof(t.begin()) i=t.begin(); i!=t.end(); i++)
#define pb push_back
#define sz size()
#define mp make_pair
#define fi first
#define se second
#define ll long long
#define IN(x,y) ((y).find((x))!=(y).end())
#define LOLDBG
#ifdef LOLDBG
#define DBG(vari) cout<<#vari<<" = "<<vari<<endl;
#define DBG2(v1,v2) cout<<(v1)<<" - "<<(v2)<<endl;
#else
#define DBG(vari)
#define DBG2(v1,v2)
#endif
#define CZ(x) scanf("%d",&(x));
#define CZ2(x,y) scanf("%d%d",&(x),&(y));
#define ALL(x) (x).begin(),(x).end()
#include <random>
#include <ctime>
using namespace std;
typedef pair<int,int> pii;
typedef vector<int> vi;
template<typename T,typename TT> ostream &operator<<(ostream &s,pair<T,TT> t) {return s<<"("<<t.first<<","<<t.second<<")";}
template<typename T> ostream &operator<<(ostream &s,vector<T> t){s<<"{";FOR(i,t.size())s<<t[i]<<(i==t.size()-1?"":",");return s<<"}"<<endl; }
mt19937 rng(time(0));
//mt19937 rng(41234);

vi kr[333];
int odw[333];
vi topo;
int global_lvl[333];
int lvl[333];
int rem[333];
int in_deg[333];
int out_deg[333];
int deg[333];

void generate_rand(int n, int m)
{
    set<pii> s;
    int iters=0;
    while(s.sz<m)
    {
        iters++;
        if (iters>(1<<21)) break;
        int a = rng()%n;
        int b = rng()%n;
        if (a<b) s.insert(mp(a,b));
    }
    FOR(i,n) kr[i].clear();
    for (auto elem : s)
    {
        kr[elem.fi].pb(elem.se);
    }
}

int levels(int n)
{
    FOR(i,n) lvl[i]=-1;
    int mx=0;
    FOR(i,n)
    {
        if (rem[i]) continue;
        if (lvl[i]==-1) lvl[i]=0;
        mx = max(mx,lvl[i]);
        for (auto v: kr[i])
        {
            lvl[v] = max(lvl[v],lvl[i]+1);
        }
    }
    return mx;
}





vi max_path(int n,int fork1=0)
{
    vi on_path(n,0);
    vi cnt_lev(n,0);
    vi path;
    int mx = levels(n);
    int cnt=0;
    REPD(i,n-1,0)
    {
        if (rem[i]) continue;
        if (lvl[i]==mx)
        {
            on_path[i]=1;
            //cnt_lev[lvl[i]]++;
        }
        else
        {
            for(auto v: kr[i])
            {
                if (!rem[v] && on_path[v] && lvl[i]+1 == lvl[v])
                {
                    on_path[i]=1;
                    cnt_lev[lvl[i]]++;
                    break;
                }
            }
        }

    }
    FOR(i,n)
    {
        if (on_path[i])
        {
            if (!fork1) path.pb(i);
            else
            {
                if (cnt_lev[lvl[i]]<=1) path.pb(i);
            }
        }
    }
    return path;

}
int mx_path = 0;
int tot=0;

int solve(int n,int k)
{
    if (k==0)
    {
        tot++;
        return levels(n);
    }
    vi path;
    if (k>=2)path = max_path(n);
    else path = max_path(n,1);
    mx_path = max(mx_path,(int)path.sz);
    int best = n;
    for(auto v: path)
    {
        if (!rem[v])
        {
            rem[v]=1;
            best = min(solve(n,k-1),best);
            rem[v]=0;
        }
    }
    return best;
}

int main()
{
    ios_base::sync_with_stdio(0);
    int n,m,k;
    cin>>n>>m>>k;
    if (n<=k)
    {
        cout<<"0\n";
        return 0;
    }
    FOR(i,m)
    {
        int a,b;
        cin>>a>>b;
        a--;b--;
        kr[a].pb(b);
    }
    FOR(i,n) rem[i]=0;
    int sol_fast = solve(n,k);
    cout<<sol_fast+1<<"\n";
}