// yukicoder 894 二種類のバス
// 2019.9.27 bal4u

#include <stdio.h>

typedef long long ll;

long long gcd(long long a, long long b)
{
	long long r;
	while (b != 0) r = a % b, a = b, b = r;
	return a;
}

ll lcm(ll a, ll b) {
	return a/gcd(a, b)*b;
}

int main()
{
	ll T, A, B, g, ans;
	
	scanf("%lld%lld%lld", &T, &A, &B);
	g = lcm(A, B);
	ans = 1+T/A + T/B - T/g;
	if (T % A == 0) ans--;
	if (T % B == 0) ans--;
	if (T % g == 0) ans++;
	printf("%lld\n", ans);
	return 0;
}