I am having trouble making a recursive method that calculates the sum of 1,2,3 to N, but does it by adding (1,2,3... to N/2) with (N/2+1... to N).

The code i manage so far is this:

```
public static void main(String[] args) {

    System.out.println(sum(10, 1));
}

public static int sum(int n, int start) {

    if (start == n){
        return n;
    }

    if (start > n / 2){
        return start + sum(n, start + 1);
    }

    return start + sum(n, start + 1);

}

```

I believe this is wrong, It is an assignment in school where we have to motivate how splitting the recursion up into to parts is a more/lesser efficient way of calculating the sum. (adding numbers from 1 to N/2 with N/2 to N, instead of just from 1 to N directly).

He made us do this way to make it harder for us but i cannot grasp the idea on how to do this at all. Is it correct? 

Thanks