#include <bits/stdc++.h>
using namespace std;

#define REP(i, n) for(ll (i) = 0; (i) < (n); (i)++)
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define MIN(a, b) ((a) < (b) ? (a) : (b))

typedef long long ll;

ll gcm(ll a, ll b){
	ll c;
	if(a < b){
		c = a; a = b; b = c;
	}
	while(b){
		c = a%b; a = b; b = c;
	}

	return a;
}

int main(void){
	ll t, a, b;
	cin >> t >> a >> b;

	vector<ll> va;
	REP(i, t){
		if(!(i%a)) va.push_back(i);
	}
	vector<ll> vb;
	REP(i, t){
		if(!(i%b)) vb.push_back(i);
	}

	ll ans = 0;
	for(ll i = 0, j = 0; i < va.size() || j < vb.size(); ){
		//cout << i << ' ' << j << endl;
		if(i == va.size()){
			ans++;
			j++;
		}else if(j == vb.size()){
			ans++;
			i++;
		}else if(va[i] == vb[j]){
			ans++; i++; j++;
		}else if(va[i] < vb[j]){
			ans++; i++;
		}else{
			ans++; j++;
		}
	}

	cout << ans << endl;

	return 0;
}