#include <iostream>
#include <cstdio>
#include <map>
#include <cstring>
using namespace std;

typedef long long LL;

const int S = 1e7 + 1, T = 2005, INF = 0x3f3f3f3f;

int primes[S], tot, fac[S], mu[S];

bool st[S];

int gcd(int a, int b) {
	return b ? gcd(b, a % b) : a;
}

map<int, int> F[T], G[T], mu2;

LL ans;

LL f(int n, int k) {
	if (n == 0) return 0;
	if (n == 1) return 1;
	if (F[k].count(n)) return F[k][n];
	else if (k > 1) {
		int p = fac[k];
		return F[k][n] = (f(n, k / p) + f(n / p, k));
	} else {
		if (n < S) return mu[n];
		int res = 1;
		for (int l = 2, r, t; l <= n; l = r + 1) {
			t = n / l, r = n / t;
			res -= f(t, k) * (r - l + 1);
		}
		return F[k][n] = res;
	}
}

LL g(int n, int k) {
	if (n == 0) return 0;
	if (G[k].count(n)) return G[k][n];
	else if (k > 1) {
		int p = fac[k];
		return G[k][n] = (g(n, k / p) - g(n / p, k / p));
	} else return n;
}

void init() {
	for (int i = 1; i < S; i++) mu[i] = 1;
	for (int i = 2; i < S; i++) {
		if (!st[i]) primes[++tot] = i, mu[i] = -1, fac[i] = i;
		for (int j = 1; primes[j] * i < S; j++) {
			st[primes[j] * i] = true;
			fac[primes[j] * i] = primes[j];
			if (i % primes[j] == 0) {
				mu[i * primes[j]] = 0;
				break;
			}
			mu[i * primes[j]] = -mu[i];
		}
	}
	for (int i = 2; i < S; i++) mu[i] += mu[i - 1];
}

int main() {
	init();
	int n, m, K; scanf("%d%d%d", &n, &m, &K);
	for (int i = 2; i <= K; i++) {
		while (K % i == 0 && (K / i) % i == 0) K /= i;
	}
	for (int l = 1, r, a, b; l <= min(n, m); l = r + 1) {
		a = n / l, b = m / l, r = min(min(n, m), min(n / a, m / b));
		ans += a * (f(r, K) - f(l - 1, K)) * g(b, K);
	}
	printf("%lld\n", ans);
	return 0;
}