#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>
#define maxn 5000 +10
using namespace std;
int n,m,sum;
int first[maxn],next[maxn * 2],father[maxn];
struct E{
	int u,v,w;
};
E edge[maxn * 2];
void add(int ,int ,int);
void Kruskal();
int mmp(E,E);
int find(int);
int main()
{
	freopen("dvalue.in","r",stdin);
	freopen("dvalue.out","w",stdout);
	scanf("%d%d",&n,&m);
	for(int i = 1; i <= n; i++) first[i] = -1;
	for(int i = 1; i <= m; i++){
		int x,y,z;
		scanf("%d%d%d",&x,&y,&z);
		add(x,y,z);
	//	add(y,x,z);
	}
	
	sort(edge + 1, edge + m,mmp);
	Kruskal();
	
}

inline void Kruskal()
{
	int MAX = -2,MIN = 2147483647;
	for(int i = 1; i <= n; i++) father[i] = i;
	int cnt= 0,tot = 0;
	for(int i = 1; i <= m; i++){
		int x = find(edge[i].u);
		int y = find(edge[i].v);
		if(x != y){
			father[x] = y;cnt++;
			tot += edge[i].w;
			MIN = min(MIN,edge[i].w);
			MAX = max(MIN,edge[i].w);
		}
		if(cnt == n-1) {
			printf("%d",MAX - MIN);
			return;
		}
	}
	
}
int find(int x)
{
	return x == father[x] ? x : father[x] = find(father[x]);
}

inline int mmp(E a, E b)
{
	return a.w < b.w;
}

void add(int x,int y,int z)
{
	edge[++sum].u = x,edge[sum].v = y,edge[sum].w = z;
	next[sum] = first[edge[sum].u];
	first[edge[sum].u] = sum;
}