#include <bits/stdc++.h>
using namespace std;
struct _ { ios_base::Init _i; _() { cin.sync_with_stdio(0); cin.tie(0); } } _;
 
#define endl '\n'
#define int intmax_t
#define in(x) for (auto& i: x)
#define test int _t; cin >> _t; for (int i=1; i<=_t; i++) {
 
signed main()
{
	int v, e, ans=INTMAX_MIN;
	cin >> v >> e;
	int g[v+1][v+1];
	for (int i=1; i<=v; i++)
		for (int j=1; j<=v; j++)
			g[i][j]=INTMAX_MAX;
	for (int i=0; i<e; i++)
	{
		int x, y, p;
		cin >> x >> y >> p;
		g[x][y]=g[y][x]=p;
	}
	for (int i=1; i<=v; i++)
		for (int j=1; j<=v; j++)
			for (int k=1; k<=v; k++)
				g[j][k]=min(g[j][k], g[j][i]+g[i][k]);
	for (int i=1; i<=v; i++)
		for (int j=1; j<=v; j++)
			if (g[i][j]!=INTMAX_MAX && i!=j)
				ans=max(ans, g[i][j]);
	cout << ans;
}

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NCA1CjEgMiAxMAoxIDMgMjQKMiAzIDIKMiA0IDE1CjMgNCA3

4 5
1 2 10
1 3 24
2 3 2
2 4 15
3 4 7