#include <bits/stdc++.h>
using namespace std;
long long res;
const long long mod = 1073741824;
long long d(int a, int b, int c) {
  vector<int> q(102, 0);
  for (int i = 2; i <= a; i++)
    if (a % i == 0) {
      while (a % i == 0) {
        a /= i;
        q[i]++;
      }
    }
  for (int i = 2; i <= b; i++)
    if (b % i == 0) {
      while (b % i == 0) {
        b /= i;
        q[i]++;
      }
    }
  for (int i = 2; i <= c; i++)
    if (c % i == 0) {
      while (c % i == 0) {
        c /= i;
        q[i]++;
      }
    }
  long long res = 1;
  for (int i = 0; i < 102; i++) res = (res * (q[i] + 1)) % mod;
  return res;
}
int main() {
  int a, b, c;
  cin >> a >> b >> c;
  for (int i = 1; i <= a; i++)
    for (int j = 1; j <= b; j++)
      for (int k = 1; k <= c; k++) res = (res % mod + d(i, j, k) % mod) % mod;
  cout << res;
}
