I
SEERC organizing committee decided to make this year's opening ceremony in unusual way - organize a parade of contestants on the city streets. This year N people (contestants, coaches and guests), that represent universities from participating countries, will go on the streets, trying to impress spectators by original costumes and loud songs. Each university is represented by a group of people and has a unique identifier (ID) that is carried by each person in the group. To make the parade well organised and entertaining, each group should be lined up in several rows, each consisting of K people.Only one university was not able to line up according to the mentioned rule, and you need to find it's ID.
Input
The first line at input contains integer N and K, separated by a single space (1 < N < 1 000 000, 2 < K < 1). Following N lines contain IDs C[1]<= C[2], ... , C[n] (0 < C[j] < 1 000 000 000, 1 < i < N) of N people.
Output
The single line at output should contain one integer - the answer for the problem.