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

using namespace std;

const int N = 100010;

int n, m;
int h[N], w[N], e[N], ne[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 ++;
}

int spfa() {
    queue<int> q;

    for(int i = 1; i <= n; i ++) {
        st[i] = true;
        q.push(i);
    }

    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;
}