#include <map>
#include <cmath>
#include <iostream>
using namespace std;

int main(int argc, char **argv)
{
  double granularity;
  map <int, double> histogram;
  map <int, double>::iterator hit;
  int bucket;
  double d;
  double total;

  if (argc != 2) {
    cerr << "usage: histogram granularity\n";
    exit(1);
  }

  total = 0;

  sscanf(argv[1], "%lf", &granularity);
  while (cin >> d) {
    bucket = floor(d /granularity);
    histogram[bucket]++;
    total++;
  }
 
  for (hit = histogram.begin(); hit != histogram.end(); hit++) {
    d = hit->first;
    d *= granularity;
    d += (granularity/2.0);
    cout << d << " " << hit->second/total << endl;
  }
  return 0;
}