#include <bits/stdc++.h>
#define rep(i,a,b) for (int (i)=(a);(i)<(b);++(i))
#define sz(x) (x).size()
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
const int INF = 1e9;
const ll LINF = 1LL<<60;
const ll MOD = 1e9+7;

ll t,a,b;
ll gcd(ll a, ll b) {
  return b?gcd(b,a%b):a;
}

int main() {
  cin>>t>>a>>b;
  ll c1 = (t-1)/a;
  ll c2 = (t-1)/b;
  ll c3 = c1/(b/gcd(a,b));
  cout << c1+c2-c3 + 1 << '\n';
  return 0;
}