/*************************************************************************
 *  Compilation:  javac Birthday.java
 *  Execution:    java Birthday N
 *  
 *  Computes the number of people (by simulation) that must enter a room
 *  until two of them share a birthday. Assumes birthdays a uniform
 *  and independent from 0 to N-1.
 *  
 *  % java Birthday 365
 *  30
 *
 *  % java Birthday 365
 *  32
 *
 *  % java Birthday 365
 *  35
 *
 *  % java Birthday 365
 *  5
 *
 *  % java Birthday 365
 *  25
 *
 *  % java Birthday 365
 *  24
 *
 *************************************************************************/


public class Birthday { 

    public static void main(String[] args) { 
        int DAYS = Integer.parseInt(args[0]);       
        boolean[] days = new boolean[DAYS];         // auto-initialized to false
        int count = 0;                              // number of people who have entered room

        while (true) {
            count++;
            int d = (int) (DAYS * Math.random());    // integer between 0 and DAYS-1
            if (days[d]) break;
            days[d] = true;
        }
        System.out.println(count);
    }
}