#include<stdio.h>
long long int gcd(long long int a, long long int b)
{
	if (b == 0)
		return a;
	else
		return gcd(b, a % b);
}
int main()
{
	long long int n, a, b;
	scanf("%lld %lld %lld", &n, &a, &b);
	long long int ans = n;
	ans -= n / a + n / b;
	long long int lcm = a / gcd(a, b) * b;
	ans += n / lcm;
	printf("%lld\n", ans);
	return 0;
}