12_arity.js

function zero() {
    console.log("Parameter is counted");
}

function one(A) {
    console.log(A);
}
function two(A, B) {
    console.log(A, B);
}
function three(A, B, C) {
    console.log(A, B, C);
}

console.log(one.length);
console.log(two.length);
console.log(three.length);