#[allow(unused_imports)]
use std::cmp::Ordering;

#[allow(unused_imports)]
use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, VecDeque};

#[allow(unused_imports)]
use std::io::{stdin, stdout, BufWriter, Write};

#[allow(unused_imports)]
use std::iter::FromIterator;

#[allow(unused_macros)]
macro_rules! min {
    ($x: expr) => ($x);
    ($x: expr, $($z: expr),+) => {{
        std::cmp::min($x, min!($($z),*))
    }}
}

#[allow(unused_macros)]
macro_rules! max {
    ($x: expr) => ($x);
    ($x: expr, $($z: expr),+) => {{
        std::cmp::max($x, max!($($z),*))
    }}
}

#[allow(unused_macros)]
macro_rules! get {
    ([$t: ty]) => {
        {
            let mut line = String::new();
            stdin().read_line(&mut line).unwrap();
            line.split_whitespace().map(|t|t.parse::<$t>().unwrap()).collect::<Vec<_>>()
        }
    };
    ([$t: ty];$n: expr) => {
        (0..$n).map(|_|get!([$t])).collect::<Vec<_>>()
    };
    ($t: ty) => {
        {
            let mut line = String::new();
            stdin().read_line(&mut line).unwrap();
            line.trim().parse::<$t>().unwrap()
        }
    };
    ($($t: ty),*) => {
        {
            let mut line = String::new();
            stdin().read_line(&mut line).unwrap();
            let mut iter = line.split_whitespace();
            ($(iter.next().unwrap().parse::<$t>().unwrap(),)*)
        }
    };
    ($t: ty; $n: expr) => {
        (0..$n).map(|_|get!($t)).collect::<Vec<_>>()
    };
    ($($t: ty),*; $n: expr) => {
        (0..$n).map(|_|get!($($t),*)).collect::<Vec<_>>()
    };
}

#[allow(unused_macros)]
macro_rules! debug {
    ($($a:expr),*) => {
        #[cfg(debug_assertions)]
        writeln!(&mut std::io::stderr(), concat!("[DEBUG] ", $(stringify!($a), "={:?} "),*), $($a),*).unwrap();
    }
}

const BIG_STACK_SIZE: bool = true;

#[allow(dead_code)]
fn main() {
    use std::thread;
    if BIG_STACK_SIZE {
        thread::Builder::new()
            .stack_size(32 * 1024 * 1024)
            .name("solve".into())
            .spawn(solve)
            .unwrap()
            .join()
            .unwrap();
    } else {
        solve();
    }
}

fn solve() {
    let (n, m, p) = get!(usize, usize, isize);
    let abc = get!(usize, usize, isize; m);

    let mut nodes = vec![Vec::new(); n + 1];
    let mut rnodes = vec![Vec::new(); n + 1];
    for &(a, b, c) in &abc {
        nodes[a].push(b);
        rnodes[b].push(a);
    }

    let mut sreach = vec![false; n + 1];
    let mut greach = vec![false; n + 1];
    sreach[1] = true;
    greach[n] = true;

    let mut queue = VecDeque::new();
    queue.push_back(1);
    while let Some(node) = queue.pop_front() {
        for &next in &nodes[node] {
            if sreach[next] {
                continue;
            }
            sreach[next] = true;
            queue.push_back(next);
        }
    }

    queue.push_back(n);
    while let Some(node) = queue.pop_front() {
        for &next in &rnodes[node] {
            if greach[next] {
                continue;
            }
            greach[next] = true;
            queue.push_back(next);
        }
    }

    let mut reach = BTreeSet::new();
    for i in 1..n + 1 {
        if sreach[i] & greach[i] {
            reach.insert(i);
        }
    }

    const INF: isize = 1_000_000_000_000_000;
    let mut dist = vec![INF; n + 1];
    dist[1] = 0;
    for i in 0..n {
        let mut updated = false;
        for &(a, b, c) in &abc {
            let c = p - c;
            if dist[b] > dist[a] + c {
                dist[b] = dist[a] + c;
                if reach.contains(&b) {
                    updated = true;
                }
            }
        }
        if i == n - 1 && updated {
            println!("-1");
            return;
        }
    }
    println!("{}", max!(0, -dist[n]));
}


Measured memory_bytes: 8572