#[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();
    }
}

#[derive(Debug)]
struct Graph {
    nodes: Vec<Vec<(usize, isize)>>,
}

impl Graph {
    fn new(n: usize) -> Self {
        Graph{
            nodes: vec![Vec::new();n+1],
        }
    }

    fn add(&mut self, src: usize, dst: usize, weight: isize) {
        self.nodes[src].push((dst, weight));
        self.nodes[dst].push((src, -weight));
    }

    fn dfs(&self, now: usize, nowv: isize, visited: &mut BTreeMap<usize, isize>) -> bool {
        for &(node, diff) in &self.nodes[now] {
            if let Some(val) = visited.get(&node) {
                if *val != nowv+diff {
                    return true;
                } else {
                    continue;
                }
            }
            visited.insert(node, nowv+diff);
            if self.dfs(node, nowv+diff, visited) {
                return true;
            }
        }
        false
    }
}


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

    let mut graph = Graph::new(n);
    for (l,r,d) in lrd {
        graph.add(l,r,d);
    }

    let mut map = BTreeMap::new();
    for i in 0..(n+1) {
        if map.contains_key(&i) {
            continue;
        }
        map.insert(i, 0);
        if graph.dfs(i, 0, &mut map) {
            println!("No");
            return;
        }
    }
    println!("Yes");
}


Measured memory_bytes: 29052