#![allow(non_snake_case, unused_imports, unused_must_use)]
use std::io::{self, prelude::*};
use std::str;

fn main() {
    let (stdin, stdout) = (io::stdin(), io::stdout());
    let mut scan = Scanner::new(stdin.lock());
    let mut out = io::BufWriter::new(stdout.lock());

    macro_rules! input {
        ($T: ty) => {
            scan.token::<$T>()
        };
        ($T: ty, $N: expr) => {
            (0..$N).map(|_| scan.token::<$T>()).collect::<Vec<_>>()
        };
    }

    let N = input!(usize);
    let M = input!(usize);
    let X = input!(usize);

    let mut edges = vec![];

    for _ in 0..M {
        let u = input!(usize);
        let v = input!(usize);
        let c = input!(usize);
        let t = input!(usize);

        edges.push((u - 1, v - 1, c + t * X));
        edges.push((v - 1, u - 1, c + t * X));
    }

    let dist = dijkstras_algorithm(N, &edges, 0)[N - 1];

    match dist {
        Some(d) => {
            writeln!(out, "{}", (d + X - 1) / X);
        }
        None => {
            writeln!(out, "-1");
        }
    }
}

pub fn dijkstras_algorithm<
    W: Sized + std::ops::Add<Output = W> + PartialOrd + Ord + Default + Clone + Copy,
>(
    size: usize,
    directed_edges: &[(usize, usize, W)],
    start: usize,
) -> Vec<Option<W>> {
    assert!(start < size);

    let graph = {
        let mut g = vec![vec![]; size];
        for &(from, to, weight) in directed_edges.iter() {
            assert!(from < size && to < size);
            g[from].push((to, weight));
        }
        g
    };

    let mut dist = vec![None; size];
    dist[start] = Some(W::default());

    let mut hq = std::collections::BinaryHeap::new();

    hq.push((std::cmp::Reverse(W::default()), start));

    while let Some((_, now)) = hq.pop() {
        for &(nxt, weight) in graph[now].iter() {
            match dist[nxt] {
                Some(prev_dist) => {
                    if dist[now].unwrap() + weight < prev_dist {
                        let d = dist[now].unwrap() + weight;
                        dist[nxt] = Some(d);
                        hq.push((std::cmp::Reverse(d), nxt));
                    }
                }
                None => {
                    let d = dist[now].unwrap() + weight;
                    dist[nxt] = Some(d);
                    hq.push((std::cmp::Reverse(d), nxt));
                }
            }
        }
    }

    dist
}

struct Scanner<R> {
    reader: R,
    buf_str: Vec<u8>,
    buf_iter: str::SplitWhitespace<'static>,
}
impl<R: BufRead> Scanner<R> {
    fn new(reader: R) -> Self {
        Self {
            reader,
            buf_str: vec![],
            buf_iter: "".split_whitespace(),
        }
    }
    fn token<T: str::FromStr>(&mut self) -> T {
        loop {
            if let Some(token) = self.buf_iter.next() {
                return token.parse().ok().expect("Failed parse");
            }
            self.buf_str.clear();
            self.reader
                .read_until(b'\n', &mut self.buf_str)
                .expect("Failed read");
            self.buf_iter = unsafe {
                let slice = str::from_utf8_unchecked(&self.buf_str);
                std::mem::transmute(slice.split_whitespace())
            }
        }
    }
}