package no168;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.InputMismatchException;
import java.util.NoSuchElementException;

public class Main {
	static IO io = new IO();
	public static void main(String[] args) {
		int n = io.nextInt();
		int[] x = new int[n];
		int[] y = new int[n];
		io.nextIntArrays(x,y);
		Kruscal g = new Kruscal(n);
		for(int i=0;i<n;i++) {
			for(int j=0;j<i;j++) {
				long dx = x[i] - x[j];
				long dy = y[i] - y[j];
				long distSq = dx * dx + dy * dy;
				long d = (sqrtCeil(distSq) + 9) / 10 * 10;
				g.addBidirectionalEdge(i, j, (int) d);
			}
		}
		System.out.println(g.minCost());
	}

	static long sqrtCeil(long n) {
		long l = 0;
		long r = 2000000000;
		while(l + 1 < r) {
			long c = (l + r) >>> 1;
			if (c * c >= n) {
				r = c;
			}else{
				l = c;
			}
		}
//		System.out.println(n + "," + r);
		return r;
	}
}
class Kruscal {
	int n;
	ArrayList<Edge> graph = new ArrayList<Edge>();

	public Kruscal(int n) {
		this.n = n;
	}

	public void addBidirectionalEdge(int u,int v,int cost) {
//		System.out.println(u + "," + v + "," + cost);
		graph.add(new Edge(cost,u,v));
	}

	public int minCost() {
		Collections.sort(graph);
		UnionFind uf = new UnionFind(n);
		int ans = 0;
		int connected = 1;
		for(int i=0;i<graph.size();i++) {
			Edge e = graph.get(i);
			if (!uf.isConnected(e.from, e.to)) {
				uf.union(e.from, e.to);
				connected++;
				ans = Math.max(ans,e.cost);
				if (connected==n) {
					break;
				}
			}
		}
		return ans;
	}

	static class Edge implements Comparable<Edge>{
		int cost;
		int from;
		int to;
		public Edge(int cost,int from,int to) {
			this.cost = cost;
			this.from = from;
			this.to = to;
		}
		@Override
		public int compareTo(Edge o) {
			if (this.cost == o.cost) {
				return 0;
			}else if(this.cost > o.cost) {
				return 1;
			}else{
				return -1;
			}
		}

		public String toString() {
			return this.cost + "," + this.from + "," + this.to;
		}
	}

	static class UnionFind {
		private int[] data;
		public UnionFind(int size) {
			data = new int[size];
			Arrays.fill(data, -1);
		}
		public void union(int x,int y) {
			x = root(x);
			y = root(y);
			if (x!=y) {
				if (data[y] < data[x]) {
					int tmp = y;
					y = x;
					x = tmp;
				}
				data[x] += data[y];
				data[y] = x;
			}
		}
		public boolean isConnected(int x,int y) {
			return root(x)==root(y);
		}
		private int root(int x) {
			return data[x] < 0 ? x : (data[x] = root(data[x]));
		}
		public int size(int x) {
			return -data[root(x)];
		}
		public String toString() {
			return Arrays.toString(data);
		}
	}
}
class IO extends PrintWriter {
	private final InputStream in;
	private final byte[] buffer = new byte[1024];
	private int ptr = 0;
	private int buflen = 0;

	public IO() { this(System.in);}
	public IO(InputStream source) { super(System.out); this.in = source;}
	private boolean hasNextByte() {
		if (ptr < buflen) {
			return true;
		}else{
			ptr = 0;
			try {
				buflen = in.read(buffer);
			} catch (IOException e) {
				e.printStackTrace();
			}
			if (buflen <= 0) {
				return false;
			}
		}
		return true;
	}
	private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
	private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
	private static boolean isNewLine(int c) { return c == '\n' || c == '\r';}
	public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
	public boolean hasNextLine() { while(hasNextByte() && isNewLine(buffer[ptr])) ptr++; return hasNextByte();}
	public String next() {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}
		StringBuilder sb = new StringBuilder();
		int b = readByte();
		while(isPrintableChar(b)) {
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	public char[] nextCharArray(int len) {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}
		char[] s = new char[len];
		int i = 0;
		int b = readByte();
		while(isPrintableChar(b)) {
			if (i == len) {
				throw new InputMismatchException();
			}
			s[i++] = (char) b;
			b = readByte();
		}
		return s;
	}
	public String nextLine() {
		if (!hasNextLine()) {
			throw new NoSuchElementException();
		}
		StringBuilder sb = new StringBuilder();
		int b = readByte();
		while(!isNewLine(b)) {
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	public long nextLong() {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}
		long n = 0;
		boolean minus = false;
		int b = readByte();
		if (b == '-') {
			minus = true;
			b = readByte();
		}
		if (b < '0' || '9' < b) {
			throw new NumberFormatException();
		}
		while(true){
			if ('0' <= b && b <= '9') {
				n *= 10;
				n += b - '0';
			}else if(b == -1 || !isPrintableChar(b)){
				return minus ? -n : n;
			}else{
				throw new NumberFormatException();
			}
			b = readByte();
		}
	}
	public int nextInt() {
		long nl = nextLong();
		if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) {
			throw new NumberFormatException();
		}
		return (int) nl;
	}
	public char nextChar() {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}
		return (char) readByte();
	}
	public double nextDouble() { return Double.parseDouble(next());}
	public int[] nextIntArray(int n) { int[] a = new int[n]; for(int i=0;i<n;i++) a[i] = nextInt(); return a;}
	public long[] nextLongArray(int n) { long[] a = new long[n]; for(int i=0;i<n;i++) a[i] = nextLong(); return a;}
	public double[] nextDoubleArray(int n) { double[] a = new double[n]; for(int i=0;i<n;i++) a[i] = nextDouble(); return a;}
	public void nextIntArrays(int[]... a) { for(int i=0;i<a[0].length;i++) for(int j=0;j<a.length;j++) a[j][i] = nextInt();}
	public int[][] nextIntMatrix(int n,int m) { int[][] a = new int[n][]; for(int i=0;i<n;i++) a[i] = nextIntArray(m); return a;}
	public char[][] nextCharMap(int n,int m) { char[][] a = new char[n][]; for(int i=0;i<n;i++) a[i] = nextCharArray(m); return a;}
	public void close() { super.close(); try {in.close();} catch (IOException e) {}}
}