#[allow(unused_imports)]
use std::cmp::{max, min};
#[allow(unused_imports)]
use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, VecDeque};
#[allow(unused_imports)]
use std::fs::File;
#[allow(unused_imports)]
use std::io::prelude::*;
#[allow(unused_imports)]
use std::io::{stdin, stdout, BufReader, BufWriter, Stdin, Stdout, Write};
#[allow(unused_imports)]
use std::mem::swap;
#[allow(unused_imports)]
use std::str::FromStr;
 
type BoxResult<T> = Result<T, Box<std::error::Error>>;
 

fn main() {
    let mut scanner = Scanner::new(stdin());
    let param = scanner.read_vector::<usize>().unwrap();
    let (n, m, p) = (param[0], param[1], param[2] as i64);
    let mut adj = vec![vec![]; n];
    for _ in 0..m {
        let line = scanner.read_vector::<usize>().unwrap();
        let (a, b, c) = (line[0] - 1, line[1] - 1, line[2] as i64);
        adj[a].push((b, p - c));
    }
    
    let reachable = bfs(0, n - 1, n, &adj);
    let mut edges = vec![];
    for i in 0..n {
        if !reachable[i] {
            continue;
        }
        for &(j, c) in adj[i].iter() {
            if !reachable[j] {
                continue;
            }
            edges.push((i, j, c));
        }
    }
    if let Some(dist) = bellman_ford(0, n - 1, n, &edges) {
        if dist > 0 {
            println!("0");
        } else {
            println!("{}", -dist);
        }
    } else {
        println!("-1");
    }
}

fn bfs(src: usize, snk: usize, n: usize, adj: &[Vec<(usize, i64)>]) -> Vec<bool> {
    let mut used = vec![false; n];
    let mut parents = vec![vec![]; n];
    let mut queue = VecDeque::new();
    queue.push_front(src);
    while queue.len() > 0 {
        let crt = queue.pop_back().unwrap();
        for &(nxt, _) in adj[crt].iter() {
            parents[nxt].push(crt);
            if used[nxt] {
                continue;
            }
            used[nxt] = true;
            queue.push_front(nxt);
        }
    }
    let mut reachable = vec![false; n];
    let mut stack = vec![snk];
    while stack.len() > 0 {
        let crt = stack.pop().unwrap();
        if reachable[crt] {
            continue;
        }
        reachable[crt] = true;
        for &nxt in parents[crt].iter() {
            if reachable[nxt] {
                continue;
            }
            stack.push(nxt);
        }
    }
    reachable
}

fn bellman_ford(src: usize, snk: usize, n: usize, edges: &[(usize, usize, i64)]) -> Option<i64> {
    let mut dist = vec![std::i64::MAX; n];
    dist[src] = 0;
    for _ in 0..(n - 1) {
        for &(s, e, c) in edges {
            if dist[s] == std::i64::MAX {
                continue;
            }
            dist[e] = min(dist[s] + c, dist[e]);
        }
    }
    for &(s, e, c) in edges {
        if dist[s] == std::i64::MAX {
            continue;
        }
        if dist[s] + c < dist[e] {
            return None;
        }
    }
    Some(dist[snk])
}


 
#[allow(dead_code)]
struct Scanner<R> {
    reader: BufReader<R>,
    buffer: String,
}
 
impl<R> Scanner<R>
where
    R: Read,
{
    #[allow(dead_code)]
    fn new(inner: R) -> Scanner<R> {
        let reader = BufReader::new(inner);
        let buffer = String::new();
        Scanner {
            reader: reader,
            buffer: buffer,
        }
    }
 
    #[allow(dead_code)]
    fn with_capacity(capacity: usize, inner: R) -> Scanner<R> {
        let reader = BufReader::with_capacity(capacity, inner);
        let buffer = String::new();
        Scanner {
            reader: reader,
            buffer: buffer,
        }
    }
 
    #[allow(dead_code)]
    fn read<T>(&mut self) -> BoxResult<T>
    where
        T: FromStr,
        T::Err: std::fmt::Debug,
        T::Err: std::error::Error,
        T::Err: 'static,
    {
        self.reader.read_line(&mut self.buffer)?;
        let parsed = self.buffer.trim().parse()?;
        self.buffer.clear();
        Ok(parsed)
    }
 
    #[allow(dead_code)]
    fn read_vector<T>(&mut self) -> BoxResult<Vec<T>>
    where
        T: FromStr,
        T::Err: std::fmt::Debug,
        T::Err: std::error::Error,
        T::Err: 'static,
    {
        self.reader.read_line(&mut self.buffer)?;
        let parsed_vec = self
            .buffer
            .trim()
            .split_whitespace()
            .map(|s| s.parse())
            .collect::<Result<Vec<_>, _>>()?;
        self.buffer.clear();
        Ok(parsed_vec)
    }
 
    #[allow(dead_code)]
    fn read_matrix<T>(&mut self, lines: usize) -> BoxResult<Vec<Vec<T>>>
    where
        T: FromStr,
        T::Err: std::fmt::Debug,
        T::Err: std::error::Error,
        T::Err: 'static,
    {
        let mut parsed_matrix = vec![];
        for _ in 0..lines {
            self.reader.read_line(&mut self.buffer)?;
            parsed_matrix.push(
                self.buffer
                    .trim()
                    .split_whitespace()
                    .map(|s| s.parse())
                    .collect::<Result<Vec<_>, _>>()?,
            );
            self.buffer.clear();
        }
        Ok(parsed_matrix)
    }
 
    #[allow(dead_code)]
    fn read_chars(&mut self) -> BoxResult<Vec<char>> {
        self.reader.read_line(&mut self.buffer)?;
        let chars = self.buffer.trim().chars().collect::<Vec<_>>();
        self.buffer.clear();
        Ok(chars)
    }
}

Measured memory_bytes: 4352