#![allow(non_snake_case, unused)]
use std::cmp::*;
use std::collections::*;
use std::f64::consts::*;

macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        let mut next = || { iter.next().unwrap() };
        input_inner!{next, $($r)*}
    };
    ($($r:tt)*) => {
        let stdin = std::io::stdin();
        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
        let mut next = move || -> String{
            bytes
                .by_ref()
                .map(|r|r.unwrap() as char)
                .skip_while(|c|c.is_whitespace())
                .take_while(|c|!c.is_whitespace())
                .collect()
        };
        input_inner!{next, $($r)*}
    };
}

macro_rules! input_inner {
    ($next:expr) => {};
    ($next:expr, ) => {};

    ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($next, $t);
        input_inner!{$next $($r)*}
    };

    ($next:expr, mut $var:ident : $t:tt $($r:tt)*) => {
        let mut $var = read_value!($next, $t);
        input_inner!{$next $($r)*}
    };
}

macro_rules! read_value {
    ($next:expr, ( $($t:tt),* )) => {
        ( $(read_value!($next, $t)),* )
    };

    ($next:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
    };

    ($next:expr, [ $t:tt ]) => {
        {
            let len = read_value!($next, usize);
            (0..len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
        }
    };

    ($next:expr, chars) => {
        read_value!($next, String).chars().collect::<Vec<char>>()
    };

    ($next:expr, bytes) => {
        read_value!($next, String).into_bytes()
    };

    ($next:expr, usize1) => {
        read_value!($next, usize) - 1
    };

    ($next:expr, $t:ty) => {
        $next().parse::<$t>().expect("Parse error")
    };
}

const INF: i64 = 1 << 50;
fn main() {
    input!{
        n: usize,
        m: usize,
        p: i64,
        mut abc: [(usize1, usize1, i64); m],
    }
    // reachability check
    let mut g:Vec<Vec<usize>> = vec![vec![]; n];
    let mut invg:Vec<Vec<usize>> = vec![vec![]; n];

    for &(a, b, _) in abc.iter() {
        g[a].push(b);
        invg[b].push(a);
    }
    let mut que = VecDeque::new();
    que.push_back(0);
    let mut reach = vec![false; n];

    while let Some(v) = que.pop_front() {
        if reach[v] {
            continue;
        }  
        reach[v] = true;
        for &w in &g[v] {
            que.push_back(w);
        }
    }
    let mut invreach = vec![false; n];
    que = VecDeque::new();
    que.push_back(n-1);
    while let Some(v) = que.pop_front() {
        if invreach[v] {
            continue;
        }  
        invreach[v] = true;
        for &w in &invg[v] {
            que.push_back(w);
        }
    }
    // ^^^ 

    // bellman-ford 
    let mut dist = vec![INF; n+1];
    dist[0] = 0;
    for i in 0..n {
        for j in 0..m {
            let mut acc = abc[j];
            if !reach[acc.1] || !invreach[acc.1] {
                continue;
            }
            acc.2 = -1 * (acc.2- p);

            if dist[acc.1] > dist[acc.0] + acc.2 {
                dist[acc.1] = dist[acc.0] + acc.2;
                if i == n-1 {
                    return println!("-1");
                }
            }
        }
    }


    println!("{}", max(-1*dist[n-1], 0));
}


Measured memory_bytes: 4352