#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<ll,ll> P;
typedef vector<ll> VI;
typedef vector<VI> VVI;
#define REP(i,n) for(int i=0;i<(n);i++)
#define ALL(v) v.begin(),v.end()
constexpr ll MOD=1000000007;
constexpr ll INF=1e18;

VVI edge(110,VI(0));

int main(){
    int n, m; cin >> n >> m;
    ll t; cin >> t;
    int a, b;
    bool f[110][110]={0};
    REP(i,m){
        cin >> a >> b;
        f[a][b]=1;
    }
    REP(i,n)REP(j,n){
        if(f[i][j])
            edge[i].push_back(j);
    }
    queue<P> q;
    q.push({0,0});
    map<P,bool> mp;
    mp[{0,0}]=1;
    while(!q.empty()){
        P p=q.front();
        if(p.second>=20000)
            break;
        q.pop();
        for(auto to:edge[p.first]){
            if(!mp[{to,p.second+1}]){
                mp[{to,p.second+1}]=1;
                q.push({to,p.second+1});
            }
        }
    }
    if(t<20000){
        int ans=0;
        REP(i,n) ans+=mp[{i,t}];
        cout << ans << endl;
    }
    else{
        int ans=0;
        REP(i,n){
            int x=-1;
            for(int j=19000;j<20000;j++){
                if(mp[{i,j}]){
                    if(x!=-1){
                        if(t%(j-x)==x%(j-x))
                            ans++;
                        break;
                    }
                    x=j;
                }
            }
        }
        cout << ans << endl;
    }
    return 0;
}