#include<bits/stdc++.h>
#include<unordered_map>
// #define int long long
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3f
#define mod 1000000007
#define MOD 998244353
#define rep(i, st, ed) for (int (i) = (st); (i) <= (ed);++(i))
#define pre(i, ed, st) for (int (i) = (ed); (i) >= (st);--(i))
#define debug(x,y) cerr << (x) << " == " << (y) << endl;
using namespace std;
typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int, int> PII;
template<typename T> inline T gcd(T a, T b) { return b ? gcd(b, a % b) : a; }
template<typename T> inline T lowbit(T x) { return x & -x; }
//template<typename T> T qmi(T a, T b = mod - 2, T p = mod) { T res = 1; b %= (p - 1 == 0 ? p : p - 1); while (b) { if (b & 1) { res = (LL)res * a % p; }b >>= 1; a = (LL)a * a % p; }return res % mod; }
const int N = 1e5 + 10;
int n, m;
vector<PII>vec[N];
int d[N], cnt[N];
bool vis[N];
bool spfa() {
    queue<int>q;
    memset(d, 0x3f, sizeof d);
    d[1] = 0;
    vis[1] = true;
    for (int i = 1; i <= n; ++i)q.push(i);
    while (q.size()) {
        int t = q.front();
        q.pop();
        vis[t] = false;
        for (int i = 0; i < vec[t].size(); ++i) {
            int j = vec[t][i].second;
            int dis = vec[t][i].first;
            if (d[j] > d[t] + dis) {
                d[j] = d[t] + dis;
                if (!vis[j])q.push(j);
                cnt[j] = cnt[t] + 1;
                if (cnt[j] >= n)return true;
            }
        }
    }
    return false;
}
void solve() {
    cin >> n >> m;
    while (m--) {
        int u, v, w; scanf("%d%d%d", &u, &v, &w);
        vec[u].push_back({ w,v });
    }
    if (spfa())puts("Yes");
    else puts("No");
}
signed main() {
    // int _; cin >> _;
    // while (_--)
        solve();
    return 0;
}