#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 lcm(int a,int b)
{
    if((double)a*b/__gcd(a,b)>2e18) return 1LL<<60;
    return a/__gcd(a,b)*b;
}

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=lcm(A,B);
    cout<<calc(T,A)+calc(T,B)-calc(T,L)<<endl;
    return 0;
}