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)

use std::collections::HashSet;
use std::io::*;

fn main() {
    let mut buf = String::new();
    stdin().read_line(&mut buf).unwrap();
    let n: i32 = buf.trim_right().parse().unwrap();

    let mut mochimochi: Vec<i32> = Vec::new();

    for _ in 0..n {
        let mut buf = String::new();
        stdin().read_line(&mut buf).unwrap();
        let num: i32 = buf.trim_right().parse().unwrap();
        mochimochi.push(num);
    }

    let uniq: HashSet<i32> = mochimochi.into_iter().collect();
    
    let out = stdout();
    let mut out = out.lock();
    writeln!(out, "{}\n", uniq.len()).unwrap();

}