#include<bits/stdc++.h>
#define int long long
using namespace std;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }

int calc(int N,int x)
{
    return (N-1)/x+1;
}

signed main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int T,A,B; cin>>T>>A>>B;
    int L=A/__gcd(A,B);
    // L*B<T
    // cout<<L<<endl;
    if(T%L==0 and B<T/L or T%L!=0 and B<=T/L){
        L*=B;
        cout<<calc(T,A)+calc(T,B)-calc(T,L)<<endl;
    } else{
        cout<<calc(T,A)+calc(T,B)-1<<endl;
    }
    return 0;
}