Problem:
Score : 300 points

Problem Statement

Find \displaystyle{\sum_{a=1}^{K}\sum_{b=1}^{K}\sum_{c=1}^{K} \gcd(a,b,c)}.

Here \gcd(a,b,c) denotes the greatest common divisor of a, b, and c.

Constraints

1 \leq K \leq 200

K is an integer.

Input

Input is given from Standard Input in the following format:

K

Output

Print the value of \displaystyle{\sum_{a=1}^{K}\sum_{b=1}^{K}\sum_{c=1}^{K} \gcd(a,b,c)}.

Sample Input 1

2

Sample Output 1

9

\gcd(1,1,1)+\gcd(1,1,2)+\gcd(1,2,1)+\gcd(1,2,2)
+\gcd(2,1,1)+\gcd(2,1,2)+\gcd(2,2,1)+\gcd(2,2,2)
=1+1+1+1+1+1+1+2=9

Thus, the answer is 9.

Sample Input 2

200

Sample Output 2

10813692

Solution in C (GCC 9.2.1) (judge verdict: Accepted)

#include <stdio.h>

int gcd(int a, int b) {
  while (b != 0) {
    int r = a % b;
    a = b;
    b = r;
  }
  return a;
}

int gcd3(int a, int b, int c) {
  return gcd(gcd(a, b), c);
}

int main(void) {
  int input;
  int sum = 0;
  scanf("%d", &input);
  for(int i = 1; i <= input; i++) {
    for(int j = 1; j <= input; j++) {
      for(int k = 1; k <= input; k++) {
        sum += gcd3(i, j, k);
      }
    }
  }
  printf("%d\n", sum);
  
  return 0;
}