#include <stdio.h>
#include <string.h>
#include <limits.h>

int main()
{
    int C, F;
    scanf("%d %d", &C, &F);

    int flights[C][C], i, j;
    for (i = 0; i < C; i++)
        for (j = 0; j < C; j++)
            flights[i][j] = -1;

    long long max_cost = LLONG_MIN;

    for (i = 0; i < F; i++) {
        int x, y;
        scanf("%d %d", &x, &y); x--; y--;
        scanf("%d", &flights[x][y]);
        flights[y][x] = flights[x][y];
    }

    for (i = 0; i < C; i++) {
        long long distance[C]; int visited[C];
        for (j = 0; j < C; j++)
            distance[j] = flights[i][j], visited[j] = 0;

        visited[i] = 1;
        while (1) {
            int min_flight = -1, min_distance = INT_MAX;
            for (j = 0; j < C; j++)
                if (distance[j] != -1 && !visited[j]
                    && distance[j] < min_distance) {
                    min_distance = distance[j];
                    min_flight = j;
                }

            if (min_flight == -1)
                break;

            visited[min_flight] = 1;
            if (min_distance > max_cost) max_cost = min_distance;
            for (j = 0; j < C; j++) {
                if (flights[min_flight][j] != -1) {
                    if (distance[j] == -1 ||
                        distance[j] > min_distance + flights[min_flight][j]) {
                        distance[j] = min_distance + flights[min_flight][j];
                    }
                }
            }
        }
    }

    printf("%lld\n", max_cost);
    return 0;
}