Teemu has written the following function.

long long solve(int n) {
    long long x = 0;
    for (int a = 1; a <= n; a++)
        for (int b = a; b <= n; b++)
            for (int c = a; c <= b; c++)
                x++;
    return x;
}

Please help Teemu to compute the value of the function for different values of n.

Input

The input consists only one number, the parameter for the function n.

Output

Output a single number, the result of the function.

Constraints

• 0 \le n \le 10^6

Example

Input:

5

Output:

35