#include <bits/stdc++.h>
using namespace std;
typedef long long  ll;
typedef vector<int> VI;
typedef vector<ll> VLL;

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

int main(){
    ll t,a,b,ans = 1,ta,tb,tl;
    cin >> t >> a >> b;

    ll lcm = a/gcd(a,b)*b;
    
    if(t%a == 0)ta = t/a-1;
    else ta = t/a;
    if(t%b == 0)tb = t/b -1;
    else tb = t/b;
    if(t%lcm == 0)tl = t/lcm -1;
    else tl = t/lcm;
    
    ans += ta + tb - tl;

    cout << ans << endl;
    return 0;
}