Java 8 solution

return  BigInteger.valueOf(n).multiply(BigInteger.valueOf(m)).longValue()-1;

In JavaScript, change these lines from "parseInt" to "toString" in main function or some test cases with big integers won't work (when you start coding, use BigInt() too):

const n = (firstMultipleInput[0]).toString();

const m = (firstMultipleInput[1]).toString();

This logic puzzle is a great way to explore algorithmic problem-solving, just like understanding Privacy Policy Details helps users grasp the structure behind data usage.

return(n*m-1)

For C++, be careful about the funciton input types. If they are the int types, you may need to change them to the long types in order to avoid any overflows.