#define _USE_MATH_DEFINES
#include<stdio.h>
#include<iostream>
#include<vector>
#include<cmath>
#include<algorithm>
#include<memory.h>
#include<map>
#include<set>
#include<queue>
#include<list>
#include<sstream>
#include<cstring>
#include<numeric>
#include<limits.h>
#include<stack>
using namespace std;




const int N = 1e2 + 1;
const int S = 1e6 + 1;
const int delta = 1e5;

int s;
vector<pair<int, int>> g[N];
set<int> gs[N];



bool mu = false;
bool k = false;

void addEdge(int a, int b, int c) {
    g[a].push_back(make_pair(b, c));
    g[b].push_back(make_pair(a, c));
    if (a == b) {
        k = true;
    }
    if (gs[a].count(b) != 0) {
        mu = true;
    }
    if (gs[b].count(a) != 0) {
        mu = true;
    }
    gs[a].insert(b);
    gs[b].insert(a);
}


bool u[N];
bool c = false;
int p[N];

void dfsCycle(int v) {
    u[v] = true;
    for (auto to : g[v]) {
        if (u[to.first]) {
            if (p[v] != to.first) {
                c = true;
                return;
            }
        }
        else {
            p[to.first] = v;
            dfsCycle(to.first);
        }
    }
}


int n, m;
int dijkstra(int s) {
    vector<int> d(n, LONG_MAX), p(n, -1);
    vector<int> r(n, 0);
    d[s] = 0;
    r[0] = 0;
    set < pair<int, int> > q;
    q.insert(make_pair(d[s], s));
    while (!q.empty()) {
        int v = q.begin()->second;
        q.erase(q.begin());

        for (size_t j = 0; j<g[v].size(); ++j) {
            int to = g[v][j].first,
                len = g[v][j].second;
            if (d[v] + len < d[to]) {
                q.erase(make_pair(d[to], to));
                d[to] = d[v] + len;
                r[to] = r[v] + 1;
                p[to] = v;
                q.insert(make_pair(d[to], to));
            }
        }
    }
    int res = 0;
    for (int i = 0; i < n; i++) {
        if (d[i] != LONG_MAX) {
            int cur = -(d[i] - delta * r[i]);
            res = max(res, cur);
        }
    }
    return res;
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
#endif
    scanf("%d%d%d", &n, &m, &s);
    for (int i = 0; i < m; i++) {
        int a, b, c;
        scanf("%d%d%d", &a, &b, &c);
        addEdge(a - 1, b - 1, -c + delta);
    }
    for (int i = 0; i < n; ++i) {
        if (!u[i]) {
            dfsCycle(i);
            if (c)
                break;
        }
    }

    if (c || mu || k) {
        printf("YES");
        return 0;
    }


    int res = 0;

    for (int i = 0; i < n; i++) {
        res = max(res, dijkstra(i));
    }


    printf(res >= s ? "YES" : "NO");


    return 0;
}