#include <iostream>
using namespace std;
typedef long long ll;
ll n,a,b,c,ans;
ll gcd(ll x,ll y){
    if(y==0)return x;
    return gcd(y,x%y);
}
int main(void){
    cin>>n>>a>>b;
    ans+=(n-1)/a+1;
    ans+=(n-1)/b+1;
    if(1e18/a>b){
        c=a/gcd(a,b)*b;
        ans-=(n-1)/c+1;
    }
    else ans--;
    cout<<ans<<endl;
}