#include <bits/stdc++.h>
using namespace std ;
const int N = 3e5 + 5, M = 1e6 + 5 ;
using ll = long long ;

//快读板子（不能读负数）
const int MS = 1e7 + 5;
namespace fast_IO {
    char buf[MS], *s, *t;
    char getchar() {
        return (s == t) && (t = (s = buf) + fread(buf, 1, MS, stdin)), s == t ? -1 : *s++;
    }
    int read() {
        int num = 0;
        char c;
        while ((c = getchar()) != '-' && c != '+' && (c < '0' || c > '9') && ~c);
        num = c ^ 48;
        while ((c = getchar()) >= '0' && c <= '9')
            num = (num << 1) + (num << 3) + (c ^ 48);
        return num;
    }
}


int n, m ;
int fa[N] ;
struct Edge
{
	int x, y, z ;
} e[M] ;
int id[M] ;

int get(int x) { return x == fa[x] ? x : fa[x] = get(fa[x]) ; }

void merge(int x, int y)
{
	int l = get(x), r = get(y) ;
	if(l != r) fa[r] = l ;
}

inline bool isUni(int x, int y)
{
	int l = get(x), r = get(y) ;
	return l == r ;
}

bool check(int mid)
{
	for(int i = 1; i <= n; ++ i) fa[i] = i ;

	for(int i = m, j = 1; i >= 1; -- i)
	{
		if(e[id[i]].z > mid) continue ;

		while(j <= m && e[id[j]].z <= mid - e[id[i]].z && e[id[j]].z <= e[id[i]].z)
			merge(e[id[j]].x, e[id[j]].y), j ++ ;

		// cout << mid << ' ' << i << ' ' << j << ' ' << isUni(1, n) << '\n' ;
		int x = e[id[i]].x, y = e[id[i]].y ;
		if(isUni(1, x) && isUni(n, y) || isUni(1, y) && isUni(n, x) || isUni(1, n))
			return 1 ;
	}
	return 0 ;
}

int main()
{
	// ios::sync_with_stdio(false) ;
	// cin.tie(nullptr) ;
	
	// cin >> n >> m ;
	n = fast_IO::read(), m = fast_IO::read() ;
	for(int i = 1; i <= m; ++ i)
	{
		int x, y, z ;
		//cin >> x >> y >> z ;
		x = fast_IO::read(), y = fast_IO::read(), z = fast_IO::read() ;
		e[i] = {x, y, z} ; id[i] = i ;
	}

	sort(id + 1, id + m + 1, [&](int x, int y) {
		return e[x].z < e[y].z ;
	}) ;

	if(m == 1) return cout << e[1].z << '\n', 0 ;

	// for(int i = 1; i <= m; ++ i) cout << id[i] << " \n"[i == m] ;
	int l = e[id[1]].z, r = e[id[m]].z + e[id[m - 1]].z ;
	// cout << l << ' ' << r << '\n' ;
	while(l < r)
	{
		int mid = (l + r) >> 1 ;
		if(check(mid)) r = mid ;
		else l = mid + 1 ;
	}

	cout << l << '\n' ;
	return 0 ;
}