#include <iostream>
#include <cstring>
#include <cmath>
#include <cstdio>
#include <cstdlib>

using namespace std;

long long f[1000001];

int main()
{
	freopen("parents.in","r",stdin);
	freopen("parents.out","w",stdout);
	long long n,m,d;
	scanf("%lld%lld%lld",&n,&m,&d);
	n/=d,m/=d;
	for (int i=min(n,m);i>=1;i--)
	{
		f[i]=(n/i)*(m/i);
		if ((n/i)!=(n/(i+1)) || (m/i)!=(m/(i+1)))
		{
			for (int j=2;j*i<=min(n,m);j++)
			f[i]-=f[j*i];
		}
		else f[i]=f[i+1];
	}
	printf("%lld\n",f[1]);
	return 0;
}