#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[8]={-1,0,1,0,1,1,-1,-1};
const ll dx[8]={0,-1,0,1,1,-1,1,-1};
template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

int main(){
    ll n,m,t;cin >> n >> m >>t;
    vector<vector<set<ll>>> dp(62,vector<set<ll>>(n));
    rep(i,m){
        ll a,b;cin >> a >> b;
        dp[0][a].ins(b);
    }
    rep(i,61){
        rep(j,n){
            set<ll> to;
            for(auto p:dp[i][j]){
                for(auto q:dp[i][p])to.ins(q);
            }
            dp[i+1][j]=to;
        }
    }
    set<ll> st;st.ins(0);
    rep(i,61){
        if(t&(1LL<<i)){
            set<ll> nst;
            for(auto p:st){
                for(auto q:dp[i][p]){
                    nst.insert(q);
                }
            }
            st=nst;
        }
    }
    cout << st.size() <<endl;
}