fn main() { let mut product: i64 = 0; for i in 1..=999 { for j in 1..=999 { let product_string: String = format!("{:?}", i*j); let reversed_string = product_string.chars().rev().collect::(); if i*j > product && reversed_string == product_string { product = i*j; } } } println!("{}", product); }