fn remove_common_letters(word1: &str, word2: &str) -> String {
word1
.chars()
.filter(|ch| !word2.contains(*ch))
.collect()
}
fn main() {
let word1 = "forest";
let word2 = "tor";
let result = remove_common_letters(word1, word2);
println!("{}", result);
}
/*
run:
fes
*/