#include <bits/stdc++.h>
#define endl '\n'
using namespace std;

const int MAXN = 10000 + 5;

map <string, int> mp;

int getInd(string s)
{
    if (mp[s]) return mp[s];
    return mp[s] = mp.size();
}

struct node
{
    int v;
    double tg;
    node () {};
    node (int _v, double _tg) {
        v = _v;
        tg = _tg;
    };
};

vector <node> G[MAXN];

double d[MAXN];

int main ()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cout << fixed << setprecision(10);

    freopen("trade.in", "r", stdin);
    freopen("trade.out", "w", stdout);

    int n; cin >> n;

    for (int i = 1; i <= n; i++)
    {
        string a, b;
        double x;
        cin >> a >> b >> x;

        int ind1 = getInd(a);
        int ind2 = getInd(b);

        G[ind1].push_back(node(ind2, x));
    }

    int bgn = getInd("BGN");

    d[bgn] = 1;

    for (int t = 1; t <= n; t++)
    {
        for (int i = 1; i <= n; i++)
        {
            for (int j = 0; j < G[i].size(); j++)
            {
                if (d[i] * G[i][j].tg > d[G[i][j].v])
                {
                    d[G[i][j].v] = d[i] * G[i][j].tg;
                }
            }
        }
    }

    for (int i = 1; i <= n; i++)
    {
        for (int j = 0; j < G[i].size(); j++)
        {
            if (d[i] * G[i][j].tg > d[G[i][j].v])
            {
                cout << "YES" << endl;
                exit(0);
            }
        }
    }

    cout << "NO" << endl;

    return 0;
}
/**

3
BGN USD 1.86
USD EUR 1.05
EUR BGN 0.52

*/