use std::collections::HashSet;


fn main() {
    let mut nmt = String::new();
    std::io::stdin().read_line(&mut nmt).ok();
    let nmt: Vec<usize> = nmt.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let n = nmt[0];
    let m = nmt[1];
    let t = nmt[2];
    let mut paths = vec![vec![false; n]; n];
    for _ in 0..m {
        let mut ab = String::new();
        std::io::stdin().read_line(&mut ab).ok();
        let ab: Vec<usize> = ab.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
        let a = ab[0];
        let b = ab[1];
        paths[a][b] = true;
    }

    let mut dp = vec![vec![HashSet::new(); n]];
    for i in 0..n {
        for j in 0..n {
            if paths[i][j] {
                dp[0][i].insert(j);
            }
        }
    }
    for i in 0..60 {
        let mut nexts = vec![HashSet::new(); n];
        for j in 0..n {
            for &u in dp[i][j].iter() {
                for &v in dp[i][u].iter() {
                    nexts[j].insert(v);
                }
            }
        }
        dp.push(nexts);
    }
    let mut result = HashSet::new();
    result.insert(0);
    for i in (0..60).rev() {
        if ((t >> i) & 1) == 0 { continue; }
        let mut nexts = HashSet::new();
        for &u in result.iter() {
            for &v in dp[i][u].iter() {
                nexts.insert(v);
            }
        }
        result = nexts;
    }
    println!("{}", result.len());
}