use std::io::*;

fn mul(a: &Vec<Vec<bool>>, b: &Vec<Vec<bool>>) -> Vec<Vec<bool>> {
    let n = a.len();
    let m = b[0].len();
    let mut c = vec![vec![false; m]; n];
    for k in 0..n {
        for i in 0..n {
            for j in 0..m {
                c[i][j] |= a[i][k] & b[k][j];
            }
        }
    }
    c
}

fn main() {
    let mut s: String = String::new();
    std::io::stdin().read_to_string(&mut s).ok();
    let mut itr = s.trim().split_whitespace();
    let n: usize = itr.next().unwrap().parse().unwrap();
    let m: usize = itr.next().unwrap().parse().unwrap();
    let mut t: usize = itr.next().unwrap().parse().unwrap();
    let mut a = vec![vec![false; n]; n];
    let mut res = vec![vec![false; n]; n];
    for _ in 0..m {
        let u: usize = itr.next().unwrap().parse().unwrap();
        let v: usize = itr.next().unwrap().parse().unwrap();
        a[v][u] = true;
        res[v][u] = true;
    }
    while t > 0 {
        if t & 1 == 1 {
            res = mul(&res, &a);
        }
        a = mul(&a, &a);
        t >>= 1;
    }
    let mut from = vec![vec![false; 1]; n];
    from[0][0] = true;
    let to = mul(&res, &from);

    let mut ans = 0;
    for i in 0..n {
        if to[i][0] {
            ans += 1;
        }
    }
    println!("{}", ans);
}