import Foundation

let answer = try String(contentsOfFile: CommandLine.arguments[1])
    .matches(of: try Regex(#"mul\(([0-9]+),([0-9]+)\)"#))
    .map { m in (Int(m.output[1].substring!), Int(m.output[2].substring!)) }
    .map { a, b in a! * b! }
    .reduce(0, +)
print(answer)