package no094;

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

public class Main {

	public static void main(String[] args) {
		IO io = new IO();
		int n = io.nextInt();
		if (n == 0) {
			System.out.println(1);
			return;
		}
		int[] x = new int[n];
		int[] y = new int[n];
		int[][] distSq = new int[n][n];
		io.arrayInt(x,y);
		UnionFind uf = new UnionFind(n);
		for(int i=0;i<n;i++) {
			for(int j=i+1;j<n;j++) {
				int dx = x[i] - x[j];
				int dy = y[i] - y[j];
				distSq[i][j] = distSq[j][i] = dx * dx + dy * dy;
				if (distSq[i][j] <= 100) {
					uf.union(i, j);
				}
			}
		}
		ArrayList<ArrayList<Integer>> groups = uf.groups();
		int maxSq = 0;
		for(ArrayList<Integer> group:groups) {
			for(int i=0;i<group.size();i++) {
				for(int j=i+1;j<group.size();j++) {
					int u = group.get(i);
					int v = group.get(j);
					maxSq = Math.max(maxSq,distSq[u][v]);
				}
			}
		}
		System.out.println(Math.sqrt(maxSq) + 2);
	}

}
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 ArrayList<ArrayList<Integer>> groups() {
		int n = data.length;
		ArrayList<ArrayList<Integer>> g = new ArrayList<ArrayList<Integer>>();
		HashMap<Integer,Integer> hm = new HashMap<Integer, Integer>();
		for(int i=0;i<n;i++) {
			int r = root(i);
			if (!hm.containsKey(r)) {
				hm.put(r, g.size());
				g.add(new ArrayList<Integer>());

			}
			g.get(hm.get(r)).add(i);
		}
		return g;
	}
	public String toString() {
		return Arrays.toString(data);
	}
}

class IO {
	private final InputStream in;
	private final PrintWriter out = new PrintWriter(System.out);
	private final byte[] buffer = new byte[1024];
	private int ptr = 0;
	private int buflen = 0;

	public IO() { this(System.in);}
	public IO(InputStream source) { 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';}
	private void skipUnprintable() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;}
	private void skipNewLine() { while(hasNextByte() && isNewLine(buffer[ptr])) ptr++;}
	public boolean hasNext() { skipUnprintable(); return hasNextByte();}
	public boolean hasNextLine() { skipNewLine(); 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 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();
		}
		while(true){
			if ('0' <= b && b <= '9') {
				n *= 10;
				n += b - '0';
			}else{
				return minus ? -n : n;
			}
			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[] arrayInt(int n) { int[] a = new int[n]; for(int i=0;i<n;i++) a[i] = nextInt(); return a;};
	public long[] arrayLong(int n) { long[] a = new long[n]; for(int i=0;i<n;i++) a[i] = nextLong(); return a;};
	public double[] arrayDouble(int n) { double[] a = new double[n]; for(int i=0;i<n;i++) a[i] = nextDouble(); return a;};
	public void arrayInt(int[]... a) {
		for(int i=0;i<a[0].length;i++) {
			for(int j=0;j<a.length;j++) {
				a[j][i] = nextInt();
			}
		}
	}
	public void println(long x) { out.println(x);}
	public void println(double x) { out.println(x);}
	public void println(String s) { out.println(s);}
	public void println() { out.println(); }
	public void print(long x) { out.print(x); }
	public void print(double x) { out.print(x); }
	public void print(String s) { out.print(s); }
	public void print(char c) {out.print(c);}
	public void flush() {out.flush(); }
}