using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using Enu = System.Linq.Enumerable;

class Program
{
    void Solve()
    {
        int N = reader.Int();
        var P = reader.IntGrid(N);
        var Es = new List<Edge>();
        Func<long, long> Sq = n => n * n;
        Func<int, int, int> Cost = (a, b) =>
        {
            long sq = Sq(P[a][0] - P[b][0]) + Sq(P[a][1] - P[b][1]);
            long len = (long)Math.Sqrt(sq) / 10 * 10;
            for (; ; len += 10) if (len * len >= sq) return (int)len;
        };

        for (int a = 0; a < N; a++)
            for (int b = 0; b < a; b++)
                Es.Add(new Edge(a, b, Cost(a, b)));
        Es.Sort();
        var uf = new UnionFind(N);
        int ans = 0;
        foreach (var e in Es)
            if (uf.Unite(e.a, e.b) && uf.Same(0, N - 1))
            {
                ans = e.cost;
                break;
            }

        Console.WriteLine(ans);
    }

    struct Edge : IComparable<Edge>
    {
        public int a, b;
        public int cost;
        public Edge(int a, int b, int c)
        {
            this.a = a; this.b = b; this.cost = c;
        }
        public int CompareTo(Edge other)
        {
            return cost.CompareTo(other.cost);
        }
    }

    class UnionFind
    {
        private int[] parent;
        private int[] rank;
        private int[] numElements;

        public UnionFind(int N)
        {
            parent = new int[N];
            rank = new int[N];
            numElements = new int[N];
            for (int i = 0; i < N; i++)
            {
                parent[i] = i;
                numElements[i] = 1;
            }
        }
        public int Root(int x)
        {
            if (parent[x] == x) return x;
            return parent[x] = Root(parent[x]);
        }
        public bool Same(int x, int y)
        {
            return Root(x) == Root(y);
        }
        public int NumElements(int x)
        {
            return numElements[Root(x)];
        }
        public bool Unite(int x, int y)
        {
            x = Root(x); y = Root(y);
            if (x == y) return false;
            if (rank[x] < rank[y])
            {
                parent[x] = y;
                numElements[y] += numElements[x];
            }
            else
            {
                parent[y] = x;
                if (rank[x] == rank[y]) { rank[x]++; }
                numElements[x] += numElements[y];
            }
            return true;
        }
    }



    Reader reader = new Reader(Console.In);
    static void Main() { new Program().Solve(); }
}

class Reader
{
    private readonly TextReader reader;
    private readonly char[] separator = { ' ' };
    private readonly StringSplitOptions removeOp = StringSplitOptions.RemoveEmptyEntries;
    private string[] A = new string[0];
    private int i;

    public Reader(TextReader r) { reader = r; }
    public Reader(string file) { reader = new StreamReader(file); }
    public bool HasNext() { return Enqueue(); }
    public string String() { return Dequeue(); }
    public int Int() { return int.Parse(Dequeue()); }
    public long Long() { return long.Parse(Dequeue()); }
    public double Double() { return double.Parse(Dequeue()); }
    public int[] IntLine() { var s = Line(); return s == "" ? new int[0] : Array.ConvertAll(Split(s), int.Parse); }
    public int[] IntArray(int N) { return Enu.Range(0, N).Select(i => Int()).ToArray(); }
    public int[][] IntGrid(int H) { return Enu.Range(0, H).Select(i => IntLine()).ToArray(); }
    public string[] StringArray(int N) { return Enu.Range(0, N).Select(i => Line()).ToArray(); }
    public string Line() { return reader.ReadLine().Trim(); }
    private string[] Split(string s) { return s.Split(separator, removeOp); }
    private bool Enqueue()
    {
        if (i < A.Length) return true;
        string line = reader.ReadLine();
        if (line == null) return false;
        if (line == "") return Enqueue();
        A = Split(line);
        i = 0;
        return true;
    }
    private string Dequeue() { Enqueue(); return A[i++]; }
}