#include <iostream>
#include <vector>
#include <algorithm>
#include <map>

using namespace std;
using ll = long long;

const int INF = 100100100;

ll gcd(ll a , ll b){
    if(a < b)swap(a , b);
    if(a % b == 0)return b;
    else return gcd(b , a % b);
}

int main(){
    ll t , a , b;
    cin >> t >> a >> b;
    ll l = a / gcd(a , b) * b;
    ll ta = t/a;
    if(t % a == 0)ta--;
    ll tb = t/b;
    if(t % b == 0)tb--;
    ll tl = (t/l);
    if(t % l == 0)tl--;
    ta = max(ta , (ll)0);
    tb = max(tb , (ll)0);
    tl = max(tl , (ll)0);
    ll ans = ta + tb - tl + 1;
    cout << ans << endl;
    return 0;
}