function Main(input) {
  input = input.split("\n");
  var N = parseInt(input[0]);
  input.shift();
  input.splice(N,input.length);
  var x = input.map(i => i.split(" ").map(i => parseInt(i)));
  var max=0;
  for(var i=0;i<N;i++){
    for(var j=i+1;j<N;j++){
      max=Math.max(max,Math.pow(x[i][0]-x[j][0],2)+Math.pow(x[i][1]-x[j][1],2));
    }
  }
  var ans = Math.sqrt(max)/2;

  console.log('%s', ans);
  return ans;
}

function debug(n){
  var input = document.getElementById("input"+n).value;
  var ans=Main(input);
  var result="WA";
  if(ans==document.getElementById("output"+n).value.split("\n")[0]){
    result="AC";
  }
  document.getElementById("result"+n).innerHTML=result;
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));