#![allow(unused_imports)]
use std::io::{ self, Write };
use std::str::FromStr;
use std::cmp::{ min, max };
use std::collections::{ BinaryHeap, VecDeque, HashMap };

#[allow(unused_macros)]
macro_rules! trace {
    ($var:expr) => {
        let _ = writeln!(&mut std::io::stderr(), ">>> {} = {:?}", stringify!($var), $var);
    };
    ($($args:expr),*) => { trace!(($($args),*)) }
}

#[allow(unused_macros)]
macro_rules! put {
    ($var:expr) => {
        let _ = writeln!(&mut std::io::stdout(), "{}", $var);
    };
    ($var:expr, $($args:expr),*) => {
        let _ = write!(&mut std::io::stdout(), "{} ", $var);
        put!($($args),*);
    };
}

type Length = i64;

#[derive(Debug)]
struct Topological(Vec<usize>);

impl Topological {

    fn visit(u: usize, mut used: &mut Vec<bool>, rd: &Vec<Vec<usize>>, mut ord: &mut Vec<usize>) {
        if used[u] { return }
        used[u] = true;
        for &v in rd[u].iter() {
            Self::visit(v, &mut used, &rd, &mut ord);
        }
        ord.push(u);
    }

    fn new(neigh: &Vec<Vec<usize>>) -> Self {
        let n = neigh.len();
        let mut rd = vec![vec![]; n];
        for u in 0..n {
            for &v in neigh[u].iter() {
                rd[v].push(u);
            }
        }
        // sort
        let mut used = vec![false; n];
        let mut ord = vec![];
        for u in 0..n { Self::visit(u, &mut used, &rd, &mut ord); }
        Topological(ord)
    }
}

fn main() {
    let mut sc = Scanner::new();
    let n: usize = sc.cin();
    let m: usize = sc.cin();

    let mut cost = HashMap::new();
    let mut neigh = vec![vec![]; n];

    for _ in 0..m {
        let u = sc.cin::<usize>() - 1;
        let v = sc.cin::<usize>() - 1;
        let d: Length = sc.cin();
        cost.insert((u, v), d);
        neigh[u].push(v);
    }

    let Topological(ord) = Topological::new(&neigh);
    // trace!(ord);

    let mut xs: Vec<Option<Length>> = vec![None; n];

    for &u in ord.iter() {

        if xs[u] == None { xs[u] = Some(0); }

        let mut stack = vec![u];
        while let Some(u) = stack.pop() {
            let x_u = xs[u].unwrap();
            for &v in neigh[u].iter() {
                let d = cost[&(u, v)];
                if d < 0 { continue }
                stack.push(v);
                // trace!(u, x_u, v, xs[v], d);
                match xs[v] {
                    None => {
                        xs[v] = Some(x_u + d);
                    },
                    Some(x) => {
                        if x != x_u + d {
                            put!("No");
                            return;
                        } else {
                            // OK
                            cost.insert((u, v), -1);
                        }
                    }
                }
            }
        }
    }

    put!("Yes");

}

#[allow(dead_code)]
struct Scanner { stdin: io::Stdin, buffer: VecDeque<String>, }
#[allow(dead_code)]
impl Scanner {
    fn new() -> Scanner { Scanner { stdin: io::stdin(), buffer: VecDeque::new() } }
    fn reserve(&mut self) {
        while self.buffer.len() == 0 {
            let mut line = String::new();
            let _ = self.stdin.read_line(&mut line);
            for w in line.split_whitespace() {
                self.buffer.push_back(String::from(w));
            }
        }
    }
    fn cin<T: FromStr>(&mut self) -> T {
        self.reserve();
        match self.buffer.pop_front().unwrap().parse::<T>() {
            Ok(a) => a,
            Err(_) => panic!("parse err")
        }
    }
}


Measured memory_bytes: 27728