#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f, maxn = 2005;
int gcd[maxn][maxn], mu[maxn], p[maxn], vis[maxn], res;
void init(int n = 2000) {
  res = 0;
  mu[1] = 1;
  for (int i = 2; i <= n; i++) {
    if (!vis[i]) p[res++] = i, mu[i] = -1;
    for (int j = 0; j < res && i * p[j] <= n; j++) {
      vis[i * p[j]] = 1;
      if (i % p[j])
        mu[i * p[j]] = -mu[i];
      else {
        mu[i * p[j]] = 0;
        break;
      }
    }
  }
  for (int i = 0; i <= n; i++) gcd[i][0] = gcd[0][i] = i;
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= i; j++) gcd[j][i] = gcd[i][j] = gcd[j][i % j];
}
int deal(int n, int d, int i) {
  int ans = 0;
  for (int j = 1; j <= n; j++)
    if (gcd[i][j * d] == 1) ans += n / j;
  return ans;
}
int main() {
  init();
  int a, b, c;
  while (~scanf("%d%d%d", &a, &b, &c)) {
    int ans = 0;
    for (int i = 1; i <= a; i++) {
      int res = 0;
      for (int d = 1; d <= min(b, c); d++) {
        res += ((long long)mu[d] * deal(b / d, d, i) * deal(c / d, d, i) %
                    1073741824 +
                1073741824) %
               1073741824;
        if (res >= 1073741824) res -= 1073741824;
      }
      ans += (long long)(a / i) * res % 1073741824;
      if (ans >= 1073741824) ans -= 1073741824;
    }
    printf("%d\n", ans);
  }
  return 0;
}
