#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<long long> VL;
typedef vector<vector<long long>> VVL;
typedef pair<int,int> Pair;
typedef tuple<int,int,int> tpl;

#define ALL(a)  (a).begin(),(a).end()
#define SORT(c) sort((c).begin(),(c).end())
#define REVERSE(c) reverse((c).begin(),(c).end())
#define EXIST(m,v) (m).find((v)) != (m).end()
#define LB(a,x) lower_bound((a).begin(), (a).end(), x) - (a).begin()
#define UB(a,x) upper_bound((a).begin(), (a).end(), x) - (a).begin()

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define RFOR(i,a,b) for(int i=(a)-1;i>=(b);--i)
#define RREP(i,n) RFOR(i,n,0)

#define en "\n"

constexpr double EPS = 1e-9;
constexpr double PI  = 3.1415926535897932;
constexpr int INF = 2147483647;
constexpr long long LINF = 1LL<<60;
constexpr long long MOD = 1000000007; // 998244353;

template<class T> inline bool chmax(T& a, T b){if(a<b){a=b;return true;}return false;}
template<class T> inline bool chmin(T& a, T b){if(a>b){a=b;return true;}return false;}

template<class T>
vector<vector<T>> matdot(vector<vector<T>>& A, vector<vector<T>>& B){
    int n = A.size(), m = B.size(), l = B[0].size();
    vector<vector<T>> ret(n, vector<T>(l,0));

    for(int i=0; i<n; i++)
        for(int j=0; j<l; j++)
            for(int k=0; k<m; k++)
                ret[i][j] = ret[i][j] || (A[i][k]&&B[k][j]);

    return ret;
}

template<class T>
void matpow(vector<vector<T>>& dp, vector<vector<T>>& mat, long long k){
    while(k){
        if(k & 1) dp = matdot(mat, dp);
        mat = matdot(mat, mat);
        k >>= 1;
    }
}

void Main(){
    ll N,M,T; cin >> N >> M >> T;
    vector<vector<bool>> mat(N,vector<bool>(N,false));
    REP(_,M){
        int a,b; cin >> a >> b;
        mat[b][a] = true;
    }

    vector<vector<bool>> dp(N,vector<bool>(1,false));
    dp[0][0] = true;

    matpow(dp,mat,T);

    int ans = 0;
    REP(i,N) if(dp[i][0]) ans++;
    cout << ans << en;
    return;
}

int main(void){
    cin.tie(0);cout.tie(0);ios_base::sync_with_stdio(0);cout<<fixed<<setprecision(15);
    int t=1; //cin>>t;
    REP(_,t) Main();
    return 0;
}