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::io;

fn main() {
    let n = get_num();
    let mut d: Vec<i32> = Vec::new();
    for _i in 0..n {
        d.push(get_num());
    }

    d.sort_by(|a, b| b.cmp(a));
    let mut step: Vec<i32> = Vec::new();

    let mut current = d[0];
    step.push(current);

    for num in d {
        if current > num {
            step.push(num);
            current = num;
        }
    }

    println!("{}", step.len());
}

fn get_num() -> i32 {
    to_i(&get_input())
}

fn to_i(s: &str) -> i32 {
    let input_num: i32 = match s.trim().parse() {
        Ok(num) => num ,
        Err(_)  => panic!("input wrong number."),
    };
    input_num
}

fn get_input() -> String {
    let mut input_str = String::new();
    io::stdin().read_line(&mut input_str)
        .expect("Failed to read line")
        ;
    input_str
}