#include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;
int n,m,father[5005],ans,cnt,minw,maxw;
struct _{
	int u,w,v;
};
_ eage[200005];
int cmp(const _& a,const _& b)
{
  	return a.v<b.v;
}
void makeset()
{
  for(int i=1;i<=n;i++)
	   father[i]=i;
}
int find(int a)
{
	return a==father[a]?a:father[a]=find(father[a]);
}
int main()
{
	freopen("dvalue.in","r",stdin);
	freopen("dvalue.out","w",stdout);
    scanf("%d%d",&n,&m);
	makeset();
	for(int i=1;i<=m;i++)
	  	scanf("%d%d%d",&eage[i].u,&eage[i].w,&eage[i].v);
    sort(eage+1,eage+m+1,cmp);
    for(int i=1;i<=m;i++)
      {
      	
      	int f1=find(eage[i].u);
      	int f2=find(eage[i].w);
      if(f1!=f2)
		{
			if(cnt==0)
			  minw=eage[i].v;
			father[f1]=f2;
			ans+=eage[i].v;
			cnt++;
			}
			if(cnt==n-1)
			{
			 maxw=eage[i].v;
			 break;
			 }
	  }
	cout<<maxw-minw;
	return 0;
	
	
}