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#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef long long ll;
typedef pair<int,int> PII;
// head

const int N=1010;

int n,m,k,ans,u,v;
int dp[N],dp2[N],pre[N],del[N],cnt[N];
VI e[N],pp;
vector<PII> mod[N],eg;

VI find() {
	int z=0;
	int posz=-1;
	for (int u=1;u<=n;u++) if (!del[u]) {
		dp[u]=1;
		pre[u]=-1;
		for (auto v:e[u]) if (!del[v]) {
			if (dp[v]+1>dp[u]) {
				dp[u]=dp[v]+1;
				pre[u]=v;
			}
		}
		if (dp[u]>z) {
			z=dp[u];
			posz=u;
		}
	}
	VI pt;
	while (1) {
		pt.pb(posz);
		posz=pre[posz];
		if (posz==-1) break;
	}
	reverse(all(pt));
	return pt;
}

bitset<310> ff[310][310];

int solvefast() {
	VI qq=pp;
	while (SZ(qq)<3) qq.pb(0);
	sort(all(qq));
	if (ff[qq[0]][qq[1]][qq[2]]) return n;
	ff[qq[0]][qq[1]][qq[2]]=1;
	int z=0;
	for (int u=1;u<=n;u++) if (!del[u]) {
		dp[u]=1;
		for (auto v:e[u]) if (!del[v]) {
			dp[u]=max(dp[u],dp[v]+1);
		}
		z=max(z,dp[u]);
	}
	for (int u=1;u<=n;u++) dp2[u]=1;
	for (int u=n;u>=1;u--) if (!del[u]) {
		for (auto v:e[u]) if (!del[v]) {
			dp2[v]=max(dp2[v],dp2[u]+1);
		}
	}
	assert(z<=60);
	for (int i=0;i<=60;i++) cnt[i]=0;
	for (int i=1;i<=n+1;i++) mod[i].clear();
	for (auto p:eg) {
		int u=p.fi,v=p.se;
		if (del[u]||del[v]) continue;
		mod[u+1].pb(mp(dp[u]+dp2[v],1));
		mod[v].pb(mp(dp[u]+dp2[v],-1));
	}
	ll st=0,mst=1ll<<61;
	for (int i=1;i<=n;i++) {
		for (auto w:mod[i]) {
			cnt[w.fi]+=w.se;
			if (w.se==1&&cnt[w.fi]==1) st^=(1ll<<w.fi);
			if (w.se==-1&&cnt[w.fi]==0) st^=(1ll<<w.fi);
		}
		if (!del[i]) mst=min(mst,st);
	}
	int ans=0;
	for (int i=1;i<=z;i++) if (mst&(1ll<<i)) ans=i;
	return ans;
}

void dfs(int dep) {
	if (dep==1) {
		ans=min(ans,solvefast());
//		ans=min(ans,SZ(find()));
	} else {
		VI w=find();
		ans=min(ans,SZ(w));
		for (auto u:w) {
			del[u]=1;
			pp.pb(u);
			dfs(dep-1);
			del[u]=0;
			pp.pop_back();
		}
	}
}

int main() {
	scanf("%d%d%d",&n,&m,&k);
	rep(i,0,m) {
		scanf("%d%d",&u,&v);
		e[v].pb(u);
		eg.pb(mp(u,v));
	}
	rep(i,1,n+1) eg.pb(mp(0,i)),eg.pb(mp(i,n+1));
	ans=SZ(find());
	if (k==0) {
		printf("%d\n",ans);
		return 0;
	}
	if (k==n) {
		puts("0");
		return 0;
	}
	dfs(k);
	printf("%d\n",ans);
}