принята

#include <iostream>
#include <vector>
#include <cmath>

const long double inf = 10000000000;

struct Agent
{
    long double x;
    long double y;
};

long double dist(Agent A, Agent B)
{
    long double x = A.x - B.x;
    long double y = A.y - B.y;
    return sqrt(x * x + y * y);
}

int main()
{
    int n;
    std::cin >> n;
    std::vector<struct Agent> agents(n);
    std::vector<std::vector<long double> > dist_matrix(n, std::vector<long double>(n));

    for (int i = 0; i < n; ++i)
        std::cin >> agents[i].x >> agents[i].y;

    for (int i = 0; i < n; ++i)
        for (int j = i + 1; j < n; ++j)
        {
            long double d = dist(agents[i], agents[j]);
            dist_matrix[i][j] = d;
            dist_matrix[j][i] = d;
        }


    std::vector<bool> is_used(n);
    std::vector<long double> min_length_to_tree(n, inf);

    min_length_to_tree[0] = 0;
    long double R = 0;

    for (int i = 0; i < n; ++i)
    {
        int best_vertex = -1;
        for (int j = 0; j < n; ++j)
            if (!is_used[j]
                && (best_vertex == -1 || min_length_to_tree[j] < min_length_to_tree[best_vertex]))
                best_vertex = j;

        if (R < min_length_to_tree[best_vertex])
            R = min_length_to_tree[best_vertex];

        is_used[best_vertex] = true;
        for (int k = 0; k < n; ++k)
            if (dist_matrix[best_vertex][k] < min_length_to_tree[k])
                min_length_to_tree[k] = dist_matrix[best_vertex][k];
    }

    std::cout.setf(std::ios::fixed);
    std::cout.precision(10);

    std::cout << R;
    return 0;
}