import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        Point[] points = new Point[n];
        for (int i = 0; i < n; i++) {
            points[i] = new Point(sc.nextInt(), sc.nextInt());
        }
        long[] costs = new long[n];
        Arrays.fill(costs, Long.MAX_VALUE);
        PriorityQueue<Path> queue = new PriorityQueue<>();
        queue.add(new Path(0, 0));
        while (queue.size() > 0) {
            Path p = queue.poll();
            if (costs[p.idx] <= p.value) {
                continue;
            }
            costs[p.idx] = p.value;
            for (int i = 0; i < n; i++) {
                if (costs[i] < Long.MAX_VALUE) {
                    continue;
                }
                queue.add(new Path(i, Math.max(p.value, points[p.idx].getDistance(points[i]))));
            }
        }
        long left = 0;
        long right = Integer.MAX_VALUE / 10;
        while (right - left > 1) {
            long m = (left + right) / 2;
            if (m * m * 100 < costs[n - 1]) {
                left = m;
            } else {
                right = m;
            }
        }
        System.out.println(right * 10);
    }
    
    static class Path implements Comparable<Path> {
        int idx;
        long value;
        
        public Path(int idx, long value) {
            this.idx = idx;
            this.value = value;
        }
        
        public int compareTo(Path another) {
            if (value == another.value) {
                return 0;
            } else if (value < another.value) {
                return -1;
            } else {
                return 1;
            }
        }
    }
    
    static class Point {
        long x;
        long y;
        
        public Point(long x, long y) {
            this.x = x;
            this.y = y;
        }
        
        public long getDistance(Point another) {
            return (x - another.x) * (x - another.x) + (y - another.y) * (y - another.y);
        }
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String nextLine() throws Exception {
        return br.readLine();
    }
    
    public String next() throws Exception {
        if (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}