#include <bits/stdc++.h>
#define rep(a,b,c) for(int a=(b);a<=(c);a++)
#define per(a,b,c) for(int a=(b);a>=(c);a--)
#define ll long long
#define vi vector<int>
#define pb emplace_back
using namespace std;

template<class T>inline void read(T &x) {
	T f=1; x=0; char s=getchar();
	while(s<'0'||s>'9'){if(s=='-')f=-1;s=getchar();}
	while(s>='0'&&s<='9'){x=x*10+s-'0';s=getchar();}
	x*=f;
}

const int N=3e5;
const int M=1e6;
struct Edge {
	int u,v,w;
}e[M+5];
inline bool cmp(Edge a,Edge b) {
	return a.w<b.w;
}

int d1[N+5],d2[N+5];
int bcj[N+5],Ans,n,m;
set<int> st[N+5];
inline int find(int x) {
	if(x==bcj[x]) return x;
	return bcj[x]=find(bcj[x]);
}

inline void upd(int x,int y,int z) {
	if(find(1)!=find(x)) return;
	if(find(n)!=find(y)) return;
	Ans=min(Ans,z+max(d1[x],d2[y]));
}

inline void get(int x,int z,int *d) {
	for(int x:st[x]) d[x]=z;
}

inline void solve() {
	read(n); read(m);
	rep(i,1,m) {
		read(e[i].u);
		read(e[i].v);
		read(e[i].w);
	}
	sort(e+1,e+m+1,cmp);
	rep(i,1,n) bcj[i]=i,st[i].insert(i);
	Ans=0x7fffffff;
	rep(i,1,m) {
		upd(e[i].u,e[i].v,e[i].w);
		upd(e[i].v,e[i].u,e[i].w);
		int x=e[i].u,y=e[i].v;
		if(find(x)==find(y)) continue;
		if(find(1)==find(x)) get(find(y),e[i].w,d1);
		if(find(1)==find(y)) get(find(x),e[i].w,d1);
		if(find(n)==find(x)) get(find(y),e[i].w,d2);
		if(find(n)==find(y)) get(find(x),e[i].w,d2);
		x=find(x); y=find(y);
		if(st[x].size()>st[y].size()) swap(x,y);
		bcj[x]=y;
		for(int X:st[x]) st[y].insert(X);
	}
	printf("%d\n",Ans);
}

int main() {
	//int T; read(T); while(T--)
	solve();
}