Check three given numbers

I would like to check 3 numbers:

• If the three numbers are same I have to display 30,
• If two numbers are same I display 40,
• Otherwise, I display 20.

When, I enter 3 numbers for example:

8
8
8

The output displays

30
40

Normally, the output is 30. Why is the value 40 added also?

let readline = require("readline-sync");

let nb1 = parseInt(readline.question("Enter nb1 please : "));
let nb2 = parseInt(readline.question("Enter nb2 please : "));
let nb3 = parseInt(readline.question("Enter nb3 please : "));


if (nb1 == nb2 && nb2 == nb3) {
    console.log(30);
}

if (nb1 == nb2 || nb2 == nb3 || nb3 == nb1) {
    console.log(40);
}

else {
    console.log(20);
}

Thanks

>Solution :

Use the second if in an else if block.
Both of the first two ifs are true when 3 numbers are equal.