#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;
const int INF = 1e9;

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

bool mu = false;
bool k = false;

void addEdge(int a, int b) {
    g[a].push_back(b);
    g[b].push_back(a);
    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]) {
            if (p[v] != to) {
                c = true;
                return;
            }
        }
        else {
            p[to] = v;
            dfsCycle(to);
        }
    }
}

int d[N][N];

int n, m;
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);
        d[a - 1][b - 1] = -c;
        d[b - 1][a - 1] = -c;
    }
    for (int i = 0; i < n; ++i) {
        if (!u[i]) {
            dfsCycle(i);
            if (c)
                break;
        }
    }

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

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (i == j) d[i][j] = 0;
            else if (d[i][j] == 0) d[i][j] = INF;
        }
    }


    int res = 0;
    for (int k = 0; k < n; ++k) {
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < n; ++j) {
                if (d[i][k] < INF && d[k][j] < INF) {
                    d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
                }
            }
        }
    }

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (d[i][j] != -INF) {
                res = max(res, -d[i][j]);
            }
        }
    }
    printf(res >= s ? "YES" : "NO");


    return 0;
}