Make Array Zero by Subtracting Equal Amounts (LC 2375 :)

In a non-negative array, each step chooses a positive integer x no greater than the current smallest non-zero element and subtracts x from every positive element; elements equal to 0 stay 0. Find the minimum number of steps to make every element zero.

输入格式

The first line contains n; the second line contains the array. 1≤n≤100, 0≤element≤100.

输出格式

Output a single integer, the answer.

样例 1

输入：

5
1 5 0 3 5

输出：

3

样例 2

输入：

1
0

输出：

0

样例 3

输入：

3
2 2 2

输出：

1

样例说明

The answers are 3, 0 and 1. Repeated equal positive values reach zero in the same operation.