#include <cstdio>
#include <utility>
#include <algorithm>
#include <map>
#include <unordered_map>
using namespace std;
const int N = 1e9;
const int K = 2e3;
const int CNT = 1e7;
int n,m,k;
int vis[CNT + 5],prime[CNT + 5],cnt,mu[CNT + 5];
int f[K + 5];
unordered_map<int,int> w;
map<pair<int,int>,long long> mem;
long long ans;
int calc(int n)
{
	if(n <= CNT)
		return mu[n];
	if(w.count(n))
		return w[n];
	long long ret = 1;
	for(register int l = 2,r;l <= n;l = r + 1)
	{
		r = n / (n / l);
		ret -= (long long)(r - l + 1) * calc(n / l);
	}
	return w[n] = ret;
}
int F(int n)
{
	return f[k] * (n / k) + f[n % k];
}
long long S(int n,int k)
{
	if(n == 0 || n == 1)
		return n;
	if(k == 1)
		return calc(n);
	if(mem.count(make_pair(n,k)))
		return mem[make_pair(n,k)];
	long long ret = 0;
	for(int i = 1;i * i <= k;++i)
		if(!(k % i))
		{
			if(mu[i] - mu[i - 1])
				ret += (mu[i] - mu[i - 1]) * (mu[i] - mu[i - 1]) * S(n / i,i);
			if(i ^ (k / i) && mu[k / i] - mu[k / i - 1])
				ret += (mu[k / i] - mu[k / i - 1]) * (mu[k / i] - mu[k / i - 1]) * S(n / (k / i),k / i);
		}
	return mem[make_pair(n,k)] = ret;
}
int main()
{
	mu[1] = 1;
	for(register int i = 2;i <= CNT;++i)
	{
		if(!vis[i])
			mu[prime[++cnt] = i] = -1;
		for(register int j = 1;j <= cnt && i * prime[j] <= CNT;++j)
		{
			vis[i * prime[j]] = 1;
			if(!(i % prime[j]))
				break;
			else
				mu[i * prime[j]] = -mu[i];
		}
		mu[i] += mu[i - 1];
	}
	scanf("%d%d%d",&n,&m,&k);
	for(register int i = 1;i <= k;++i)
		f[i] = f[i - 1] + (__gcd(i,k) == 1);
	for(register int l = 1,r;l <= min(n,m);l = r + 1)
	{
		r = min(n / (n / l),m / (m / l));
		ans += (S(r,k) - S(l - 1,k)) * (n / l) * F(m / l);
	}
	printf("%lld\n",ans);
}