#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

long long int GCD(long long int x, long long int y){
    if(x>y){
        long long int swap = x;
        x = y;
        y = swap;
    }
    while(true){
        if(y%x==0){
            return x;
        }else{
            long long int amari = y%x;
            y = x;
            x = amari;
        }
    }
}

int main() {
    ll t,a,b;
    cin >> t >> a >> b;
    ll a_ = a / GCD(a, b);
    ll INF = 1e18 + 7;
    ll c = INF;
    if(t / a_ >= b) c = a_ * b;
    ll ans = (t - 1) / a + 1 + (t - 1) / b + 1 - ((t - 1) / c + 1);
    

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