/*
 * Solution to "Party, Party, Party"
 * (Not very efficient, but maybe it doesn't need to be.)
 */

import java.util.*;

// Container class for party: just a "start" and an "end" time

class Pair implements Comparable<Pair> {
  public int s, e;
  public Pair(int s, int e) {
    this.s = s; this.e = e;
  }


  public int compareTo(Pair o) {
    if (this.s < o.s)
      return -1;
    else if (this.s > o.s)
      return 1;
    else if (this.e < o.e)
      return -1;
    else if (this.e > o.e)
      return 1;
    else return 0;
  }
}

public class Party {
  public static Scanner in;
  public static int p; // number of parties going on
  public static int caseNum; // day number
  public static Pair party[]; // all the parties being held

  public static void main(String[] args) {
    in = new Scanner(System.in);
    caseNum = 0;
    while ((p = in.nextInt()) > 0) {
      caseNum++;

      // Input the party information:
      party = new Pair[p];
      for (int i = 0; i < p; i++) {
        int s = in.nextInt();
        int e = in.nextInt();
        party[i] = new Pair(s,e);
      }

      // Sort parties, first by start time, and for identical start times,
      // by end time. (Latter condition not really needed for my solution.)
      Arrays.sort(party);

      // It's going to be convenient to delete parties from the list, so
      // convert from array to ArrayList:
      List<Pair> l = Arrays.asList(party);
      ArrayList<Pair> al = new ArrayList<Pair>(l);

// Debug:
// for (int i = 0; i < p; i++)
//   System.out.printf("%d %d\n",party[i].s,party[i].e);

      int loc = 0; // Always begin searching list at position "loc"
      int answer = 0; // number of parties Emma can attend

      // For each hour, run through the list and see if there is a party
      // then.
      //for (int time = 8; time <= 23; time++) {
      for (int half = 0; half < 33; half++) {
        double time = 8 + half*.5;
        if (loc >= al.size())
          break;

        // Now search for the eligible party with earliest ending time:
        int j = loc;
        int min = 25;
        int minLoc = j;
        while (j < al.size()) {
          Pair x = al.get(j);
          if (x.s > time) 
            break; // This is not an eligible party -- hasn't started yet

          if (x.e > time && x.e < min) {
            minLoc = j; 
            min = x.e;
          }
          j++;
        }
        // If we found an eligible party, count it and remove it from the list:
        if (min < 25) {
          answer++;

// Debug:
// System.out.println("("+al.get(minLoc).s+","+al.get(minLoc).e+")");

          al.remove(minLoc);
        }
      }
      System.out.println("On day " + caseNum + " Emma can attend as many as " 
          + answer + " parties.");
    }
  }
}