You have an array of nn integers, and you want to find how many unique elements it has. An element is unique if it only appears once in the array.
For example, the array [5,7,8,5,4,4,3][5,7,8,5,4,4,3] contains 3 unique elements: 77, 88, and 33. 55 is not a unique element, since it occurs twice in the array.
The first line of input contains a single positive integer nn (1<=n<=200000)(1<=n<=200000): the length of the array.
The next line contains nn space-separated integers: the array. The array elements will be between 11 and 109109, inclusive.
Output a single positive integer: the number of unique elements in the array.