#include <stdio.h>

void chmin(long long* a, long long b)
{
	if (*a > b) *a = b;
}

long long count(long long N, long long M)
{
	int i, j, k, m[100] = {};
	long long p[100];
	for (i = 2, k = 0; M / i >= i; i++) {
		if (M % i == 0) {
			p[k] = i;
			while (M % i == 0) {
				M /= i;
				m[k]++;
			}
			k++;
		}
	}
	if (M > 1) {
		p[k] = M;
		m[k++] = 1;
	}
	
	long long ans = 1LL << 60, tmp, X;
	for (i = 0; i < k; i++) {
		for (X = p[i], tmp = 0; 1; X *= p[i]) {
			tmp += N / X;
			if (X > N / p[i]) break;
		}
		chmin(&ans, tmp);
	}
	return ans;
}

int main()
{
	long long N, K, M;
	scanf("%lld %lld %lld", &N, &K, &M);
	printf("%lld\n", count(N, M) - count(N - K, M) - count(K, M));
	fflush(stdout);
	return 0;
}