use std::collections::HashMap;

fn main() {
    let mut squares = HashMap::new();
    squares.insert("one", 1);
    squares.insert("two", 4);
    squares.insert("three", 9);
    for key in squares.keys() {
        println!("Key {}", key);
    }
    for value in squares.values() {
        println!("Value {}", value);
    }
    for (key, value) in squares.iter() {
        println!("{} => {}", key, value);
    }
}