#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<cassert>
#include<complex>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
const ll mod = 1000000007;
const ll INF = mod * mod;
typedef pair<int, int>P;
typedef pair<int, bool> sP;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
typedef pair<ll, ll> LP;
typedef vector<ll> vec;
typedef long double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-5;
const ld pi = acos(-1.0);
typedef vector<vector<ll>> mat;
typedef vector<ll> vec;

ll gcd(ll a, ll b) {
	if (a < b)swap(a, b);
	while (b) {
		ll r = a % b; a = b; b = r;
	}
	return a;
}
void solve() {
	ll t, a, b; cin >> t >> a >> b; t--;
	ll ca = t / a + 1;
	ll cb = t / b + 1;
	ll g = gcd(a, b);
	ld xa = log(a/g); ld xb = log(b/g); ld xg = log(g);
	ld xt = log(t);
	ll cab = 1;
	if (xt - eps >= xa + xb+xg) {
		cab = t / ((a/g)*b) + 1;
	}
	cout << ca + cb - cab << endl;
}


signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//init();
	solve();
	//stop
	return 0;
}