#include<iostream>
#include<cstring>
#include<queue>

using namespace std;
const int N = 1e5 + 10;
int n, m;
int h[N], e[N], ne[N], w[N], idx;
int dist[N], cnt[N];
bool st[N];
void add(int a, int b, int c)
{
    e[idx] = b;
    w[idx] = c;
    ne[idx] = h[a];
    h[a] = idx ++;
}
bool spfa()
{
    queue<int> q;
    for (int i = 1; i <= n; i ++) {
		q.push(i);
		st[i] = true;
	}
	while (q.size()) {
		int t = q.front();
		q.pop();
		st[t] = false;
		for (int i = h[t]; i != -1; i = ne[i]) {
			int j = e[i];
			if (dist[j] > dist[t] + w[i]) {
				dist[j] = dist[t] + w[i];
				cnt[j] = cnt[t] + 1;
				if (cnt[j] >= n)	return true;
				if (!st[j]) {
					q.push(j);
					st[j] = true;
				}
			}
		}
	}
	return false;
}
int main()
{
    cin >> n >> m;
    memset(h, -1, sizeof h);
    while (m --) {
        int a, b, c;
        cin >> a >> b >> c;
        add(a, b, c);
    }
    if (spfa())	puts("Yes");
    else	puts("No");
    return 0;
}