/*** author: yuji9511 ***/
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> lpair;
const ll MOD = 1e9 + 7;
const ll INF = 1e18;
#define rep(i,m,n) for(ll i = (m); i < (n); i++)
#define rrep(i,m,n) for(ll i = (m); i >= (n); i--)
#define printa(x,n) for(ll i = 0; i < n; i++){ cout << (x[i]) << " \n"[i==n-1];};
void print() {}
template <class Head, class... Tail>
void print(Head&& head, Tail&&... tail){ cout << head << " \n"[sizeof...(tail) == 0]; print(forward<Tail>(tail)...);}
inline ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
inline ll lcm(ll a,ll b){return a/gcd(a,b)*b;}
int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	ll T,A,B;
	cin >> T >> A >> B;
	ll ans = (T+A-1) / A + (T+B-1) / B;
	double d = (double) A * (double) B;
	if(d <= 9e18){
		ans -= (T + lcm(A,B)-1) / lcm(A,B);
	}
	print(ans);
	
}