// LVJ submission #65bfbbafce3cbd022bb81820@1707064240656
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <map>

typedef long long LL;
const int MK = 2005;
const int S = 31622;
const int MN23 = 1000005;
const int MP = 78505;
const int MD = 25;

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

bool ip[MN23];
int p[MP], pc;
int mu[MN23], Smu[MN23];

inline void Init(int N) {
	mu[1] = 1;
	for (int i = 2; i <= N; ++i) {
		if (!ip[i]) p[++pc] = i, mu[i] = -1;
		for (int j = 1; j <= pc && p[j] * i <= N; ++j) {
			ip[p[j] * i] = 1;
			if (i % p[j]) mu[p[j] * i] = -mu[i];
			else break;
		}
	}
	for (int i = 1; i <= N; ++i) Smu[i] = Smu[i - 1] + mu[i];
}

int N, M, K, N23;
int A[MK], Vl[MD], cd;

std::map<int, LL> mp[MD];

LL Sum(int N, int K) {
	if (!N) return 0;
	if (K == 1 && N <= N23) return Smu[N];
	if (mp[K].count(N)) return mp[K][N];
	if (K > 1) {
		LL Ans = 0;
		for (int j = 1; j <= K; ++j)
			if (Vl[K] % Vl[j] == 0 && mu[Vl[j]])
				Ans += Sum(N / Vl[j], j);
		return mp[K][N] = Ans;
	}
	LL Ans = 1;
	for (int i = 2, j; i <= N; i = j + 1) {
		j = N / (N / i);
		Ans -= (j - i + 1) * Sum(N / i, 1);
	}
	return mp[1][N] = Ans;
}

LL Ans;

int main() {
	scanf("%d%d%d", &N, &M, &K);
	for (int i = 1; i <= K; ++i) A[i] = A[i - 1] + (gcd(i, K) == 1);
	Init(N23 = std::max((int)pow(N, 2./3), K));
	for (int i = 1; i <= K; ++i) if (K % i == 0 && (mu[i] || i == K)) Vl[++cd] = i;
	for (int i = 1, kN, kM, j; i <= N && i <= M; i = j + 1) {
		kN = N / i, kM = M / i;
		j = std::min(N / kN, M / kM);
		Ans = Ans + kN * ((LL)kM / K * A[K] + A[kM % K]) * (Sum(j, cd) - Sum(i - 1, cd));
	}
	printf("%lld\n", Ans);
	return 0;
}