#include <iostream>
#include <cstring>
using namespace std;
const int N = 20010, M = 200010;
int n, m;
int h[N], e[M], w[M], ne[M], idx;
int color[N];
void add(int a, int b, int c)
{
e[idx] = b, w[idx] = c, ne[idx] = h[a], h[a] = idx ++ ;
}
bool dfs(int u, int c, int mid)
{
color[u] = c;
for (int i = h[u]; ~i; i = ne[i])
{
if (w[i] <= mid) continue;
int j = e[i];
if (color[j])
{
if (color[j] == color[u]) return false;
}
else if (!dfs(j, 3 - c, mid)) return false;
}
return true;
}
bool check(int mid)
{
memset(color, 0, sizeof color);
for (int i = 1; i <= n; i ++ )
if (!color[i])
if (!dfs(i, 1, mid)) return false;
return true;
}
int main()
{
scanf("%d%d", &n, &m);
memset(h, -1, sizeof h);
while (m -- )
{
int a, b, c;
scanf("%d%d%d", &a, &b, &c);
add(a, b, c), add(b, a, c);
}
int l = 0, r = 1e9;
while (l < r)
{
int mid = l + r >> 1;
if (check(mid)) r = mid;
else l = mid + 1;
}
printf("%d\n", r);
return 0;
}