#include<bits/stdc++.h>
using namespace std;
const int MAXN=3e5+5,MAXM=1e6+5;
int fa[MAXN],n,m;
long long d[MAXN];
struct edge{
	int u,v;
	long long w;
};
vector<edge> g[MAXN];
edge e[MAXM];
long long ans=1e15;
int findf(int x){
	if(x==fa[x])
		return fa[x];
	fa[x]=findf(fa[x]);
	return fa[x];
}
bool cmp(edge u,edge v){
	return u.w<v.w;
}
// 快读 

int read(){
	int x = 0, f = 1;
	char c = getchar();
	while(c < '0' || c > '9'){
		if(c == '-'){
			f = -1;
		}
		c = getchar();
	}
	while(c >= '0' && c <= '9'){
		x = x*10+c-'0';
		c = getchar();
	}
	return x*f;
}
void addedge(int u,int v,int w){
	edge tmp;
	tmp.v=v,tmp.w=w;
	g[u].push_back(tmp);
}
void dfs(int u,int fat,long long cur){
	d[u]=max(d[fat],cur);
	for(auto i=g[u].begin();i!=g[u].end();++i){
		int v=(*i).v,w=(*i).w;
		if(v==fat)
			continue;	
		dfs(v,u,w);
	}
}
int main(){
	n=read(),m=read();
	for(int i=1;i<=m;++i){
		e[i].u=read(),e[i].v=read(),e[i].w=read();
	}
	sort(e+1,e+1+m,cmp);
	for(int i=1;i<=n;++i)
		fa[i]=i;
		
	for(int i=1;i<=m;++i){
		int r1=findf(e[i].u);
		int r2=findf(e[i].v);
		int t1=findf(1),t2=findf(n);
		if(r1!=r2){
			if(r1==t1&&r2==t2||r1==r2&&r2==t1){
				ans=min(ans,max(d[e[i].u],d[e[i].v])+e[i].w);
			}
			else{
				fa[r2]=r1;
				addedge(e[i].u,e[i].v,e[i].w);
				addedge(e[i].v,e[i].u,e[i].w);
				if(r1==t1||r1==t2){
					dfs(e[i].v,e[i].u,e[i].w);
				}
				if(r2==t1||r2==t2){
					dfs(e[i].u,e[i].v,e[i].w);
				}
			}			
		}
	} 
/*	for(int i=1;i<=n;++i)
		cout<<d[i]<<" ";
	cout<<endl;*/
	cout<<ans;
}