/* Topcoder SRM 700, D1, 300-Pointer (FindingFriend)
 * James S. Plank
 * Wed Oct 26 11:16:37 EDT 2016
 */

#include <vector>
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstdlib>
using namespace std;

class FindingFriend
{
    public:
        int find(int roomSize, vector <int> leaders, int friendPlace);
};

int FindingFriend::find(int roomSize, vector <int> leaders, int friendPlace)
{
    /* These are the three variables described in the writeup. */

    int r;
    int leftover;
    int rooms;

    /* The first step is sorting, and checking to make return one when 
       friendPlace equals one of the leaders. */
      
    sort(leaders.begin(), leaders.end());

    for (r = 0; r < leaders.size(); r++) {
      if (friendPlace == leaders[r]) return 1;
    }

    /* We set r, leftover and rooms before we start our main algorithm. */

    r = 0;
    leftover = 0;
    rooms = 0;

    while (1) {

        /* First step -- increment r, and if our loop is done, return (rooms+1). */

        r++;
        if (r == leaders.size()) return rooms+1;

        /* Now, we're adding the number of available contestant slots from room r-1
           into leftover, and incrementing rooms to reflect adding room r-1 */

        leftover += (roomSize-1);
        rooms++;

        /* If friendPlace is less than the leader for room r, then your friend has
           to go into one of the previous rooms.  Return rooms. */

        if (friendPlace < leaders[r]) return rooms;

        /* Decrement leftover by the number of contestants that must go into a
           room less than r.  If that number is now zero, then we need to set 
           rooms to zero, because there are no slots left in any of those rooms. */

        leftover -= (leaders[r]-leaders[r-1]-1);
        if (leftover == 0) rooms = 0;
    }

    return 0;                                     /* Shut the compiler up. */
}