Little Sub is an ICPC participant.
Every time when Little Sub solves a new problem, a balloon will be given to him. Different problems have distinct colors.
However, volunteers may give multiple balloons of the same kind to participants when they solve the problem.
Little Sub forgets how many problems he has solved in the last competition, but he still remember all balloons he received. Please help him calculate the number of passed problems.
The first line contains one positive integer n(1 ≤ n ≤ 100), indicating the number of balloons. The following line contains n integers, indicating all the balloons. To simplify the problem, we mark
different colors as different ids.
All given integers will not exceed 2^31 − 1.
Print one integer on the single line, indicating the answer.