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 (1.42.0) (judge verdict: Accepted)

use std::collections::HashSet;

fn solve(mut ds: Vec<u8>) -> usize {
    ds.sort();
    ds.into_iter().collect::<HashSet<u8>>().len()
}

fn main() {
    let n = read_1();
    let ds = read_1_n(n);

    println!("{}", solve(ds));
}

fn read_1<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn read_1_n<T: std::str::FromStr>(n: usize) -> Vec<T> {
    let mut ss = String::new();
    for _ in 0..n {
        std::io::stdin().read_line(&mut ss).ok();
    }
    let mut v = ss.split("\n").collect::<Vec<&str>>();
    v.pop();
    v.iter()
        .map(|s| s.trim().parse().ok().unwrap())
        .collect()
}