function Main(input) {
  input = input.trim()
  input = input.split("\n");
  var N = input[0];
  input.shift();
  var arr =[];
  var max = 0;
  for(var i=0;i<N;i++){
  var mem = input[i].split(" ").map(Number);
  for(var j=0;j<arr.length;j++){
    var x1 = mem[0];
    var x2 = arr[j][0];
    var y1 = mem[1];
    var y2 = arr[j][1];
    var A = Math.sqrt( Math.pow( x2-x1, 2 ) + Math.pow( y2-y1, 2 ) ) ;
    if(A>max) max = A;
  }
  arr.push(mem)
  }
  console.log(max/2)
}Main(require("fs").readFileSync("/dev/stdin", "utf8"));