/// Author : Nguyễn Thái Sơn - K18 - KHMT - UIT
/// Training ICPC 2024

#include<bits/stdc++.h>

/// #pragma GCC optimize("O3,unroll-loops")
/// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

#define fi first
#define se second
#define TASK "test"
#define pb push_back
#define EL cout << endl
#define Ti20_ntson int main()
#define in(x) cout << x << endl
#define all(x) (x).begin(),(x).end()
#define getbit(x, i) (((x) >> (i)) & 1)
#define cntbit(x) __builtin_popcount(x)
#define FOR(i,l,r) for (int i = l; i <= r; i++)
#define FORD(i,l,r) for (int i = l; i >= r; i--)
#define Debug(a,n) for (int i = 1; i <= n; i++) cout << a[i] << " "; cout << endl

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> vii;
typedef unsigned long long ull;
typedef vector<vector<int>> vvi;
int fastMax(int x, int y) { return (((y-x)>>(32-1))&(x^y))^y; }

const int N = 1e4 + 5;
const int oo = INT_MAX;
const int mod = 1e9 + 7;
const int d4x[4] = {-1, 0, 1, 0} , d4y[4] = {0, 1, 0, -1};
const int d8x[8] = {-1, -1, 0, 1, 1, 1, 0, -1}, d8y[8] = {0, 1, 1, 1, 0, -1, -1, -1};

int n, m;
tuple<int, int, int> Canh[N];
vector<int> dsk[N];
bool visited[N];

inline void Read_Input() {
    cin >> n >> m;

    for (int i = 1; i <= m; i++) {
        int u, v, w;
        cin >> u >> v >> w;
        Canh[i] = {u, v, w};
    }
}

void dfs(int u, int p) {
    visited[u] = true;
    for (int v : dsk[u])
        if (v != p)
            dfs(v, u);
}

bool Check(int val) {
    /// B2 : tạo đồ thị mới với những cạnh có trọng số <= x

    /// Bắt đầu làm là chưa có gì
    FOR(i, 1, n)
        visited[i] = false, dsk[i].clear();

    FOR(i, 1, m) {
        auto[u, v, w] = Canh[i];

        if (w <= val) {
            dsk[u].push_back(v);
            dsk[v].push_back(u);
        }
    }

    dfs(1, 1);

    if (visited[n] == true) return true;
    return false;
}

inline void Solve() {
    /// B1 : chặt nhị phân giá trị x để kiếm tra

    int l = 1, r = 1e9;
    int Ans = -1;

    while (l <= r) {
        int mid = (l + r) / 2;

        if (Check(mid) == true) {
            /// Check gia tri 5 = dung

            /// [5, 6, 7 ... , 1e9] = dung

            /// [1, 4]

            r = mid - 1;
            Ans = mid;
        }
        else l = mid + 1;
    }

    cout << Ans;

}

Ti20_ntson {
//    freopen(TASK".INP","r",stdin);
//    freopen(TASK".OUT","w",stdout);
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    int T = 1;
//    cin >> T;
    while (T -- ) {
        Read_Input();
        Solve();
    }
}