Problem:
Score : 200 points

Problem Statement

An X-layered kagami mochi (X ≥ 1) is a pile of X round mochi (rice cake) stacked vertically where each mochi (except the bottom one) has a smaller diameter than that of the mochi directly below it. For example, if you stack three mochi with diameters of 10, 8 and 6 centimeters from bottom to top in this order, you have a 3-layered kagami mochi; if you put just one mochi, you have a 1-layered kagami mochi.

Lunlun the dachshund has N round mochi, and the diameter of the i-th mochi is d_i centimeters. When we make a kagami mochi using some or all of them, at most how many layers can our kagami mochi have?

Constraints

1 ≤ N ≤ 100

1 ≤ d_i ≤ 100

All input values are integers.

Input

Input is given from Standard Input in the following format:

N
d_1
:
d_N

Output

Print the maximum number of layers in a kagami mochi that can be made.

Sample Input 1

4
10
8
8
6

Sample Output 1

3

If we stack the mochi with diameters of 10, 8 and 6 centimeters from bottom to top in this order, we have a 3-layered kagami mochi, which is the maximum number of layers.

Sample Input 2

3
15
15
15

Sample Output 2

1

When all the mochi have the same diameter, we can only have a 1-layered kagami mochi.

Sample Input 3

7
50
30
50
100
50
80
30

Sample Output 3

4

Solution in Rust (1.15.1) (judge verdict: Accepted)

fn main() {
    let scan = std::io::stdin();
    let mut line = String::new();
    let _ = scan.read_line(&mut line);
    let vec: Vec<&str> = line.split_whitespace().collect();
    let n: i32 = vec[0].parse().unwrap();

    let mut ans: i32 = 0;
    let mut data: Vec<i32> = Vec::new();

    for _ in 0..n{
        let mut line = String::new();
        let _ = scan.read_line(&mut line);
        let vec: Vec<&str> = line.split_whitespace().collect();
        data.push(vec[0].parse().unwrap());
    }

    'l1:loop{
        if data.len() == 0{
            break 'l1;
        }
        let n = data.pop().unwrap();
        data.retain(|&x| x != n);
        ans = ans + 1;
    }

    println!("{}",ans);
}