#include<bits/stdc++.h>
using namespace std;
int ans;
int n,m;
bool dmmap[100001];
struct node{
	vector<int> g,s;
}mmap[100001];
int dfs(int f,int t)
{
	int dans=0;
	for(int i(0);i<mmap[f].g.size();i++)
	{
		if(!(dmmap[mmap[f].g[i]]))
		{
			dmmap[mmap[f].g[i]]=1;
			ans=max(ans,dfs(mmap[f].g[i],t+mmap[f].s[i]));
			dmmap[mmap[f].g[i]]=0;
		}
	}
	return ans+t;
}
int main()
{
	cin.tie(0);
	cout.tie(0);
	ios_base::sync_with_stdio(0);
	
	cin>>n>>m;
	for(int i=1;i<=n;i++)
	{
		int x,y,z;
		cin>>x>>y>>z;
		mmap[x].g.push_back(y);
		mmap[x].g.push_back(z);
		mmap[y].g.push_back(x);
		mmap[y].g.push_back(z);
	}
	for(int i(1);i<=n;i++)
	{
//		memset(dmmap,000000000,sizeof(dmmap));
		ans=max(ans,dfs(i,0));
	}
	cout<<ans;
	return 0;
}
//register 
//\n %d

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