fn read() -> Vec { let mut s = String::new(); std::io::stdin().read_line(&mut s).unwrap(); s.trim().bytes().rev().map(|x| x - b'0').collect::>() } fn main() { let a = read(); let b = read(); let mut ans = String::new(); let mut carry = 0; for i in 0.. { if i >= a.len() && i >= b.len() && carry == 0 { break; } let mut tmp = carry; if i < a.len() { tmp += a[i]; } if i < b.len() { tmp += b[i]; } carry = tmp / 10; tmp -= tmp / 10 * 10; ans = format!("{}{}", tmp, ans); } println!("{}", ans); }