#include<bits/stdc++.h>
using namespace std;

#define rep(i,n) for(ll i=0;i<(n);++i)
using ll = unsigned long long;
using pll = pair<ll,ll>;
constexpr ll INF = (1LL<<60);
constexpr ll MOD = (1e9+7);
//constexpr ll MOD = (998244353);
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;}
void dump(){cout<<endl;}
template<class T,class... Ts> void dump(T&& h, Ts&&... t){cout<<h<<", ";dump(forward<Ts>(t)...);}
template<class T> istream &operator>>(istream&is,vector<T>&v){for(auto &elemnt:v)is>>elemnt;return is;}
template<class T,class U> istream &operator>>(istream&is,pair<T,U>&p){is>>p.first>>p.second;return is;}
template<class T>vector<T> make_vector(size_t a){return vector<T>(a);}
template<class T, class... Ts>auto make_vector(size_t a, Ts... ts){return vector<decltype(make_vector<T>(ts...))>(a, make_vector<T>(ts...));}

void solve1();void solve2();
int main(){
  solve1();
  return 0;
}

template<typename T>T my_gcd(T a,T b){while(1){swap(a,b);if(a==0)return b;if(b==0)return a;a%=b;}}
template<class T>inline T my_lcm(T a,T b){return a/my_gcd(a,b)*b;}

void solve1(){

  ll t,a,b;
  cin>>t>>a>>b;

  cout<<(t-1)/a+(t-1)/b-(t-1)/my_lcm(a,b)+1<<endl;

}