#include <bits/stdc++.h>
    using namespace std;
    #include <math.h>
    #include <iomanip>
    #include <cstdint>
    #include <string>
    #include <sstream>
    template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
    template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
    #define rep(i,n) for (int i = 0; i < (n); ++i)
    typedef long long ll;
    typedef long double ld;
    typedef unsigned long long ull;
    using P=pair<ll,ll>;
    const ll INF=1e18;
    const int mod=998244353;

    void solve(){
        ll t,a,b;
        cin>>t>>a>>b;
        ll l=a/__gcd(a,b)*b;
        ll ans=(t-1)/a+(t-1)/b-(t-1)/l+1;
        cout<<ans<<endl;
    } 
    int main(){
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        
        solve();  

        return 0;
    }