#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
#define rrep(i,n) for(int (i)=((n)-1);(i)>=0;(i)--)
#define itn int
#define all(x) (x).begin(),(x).end()
#define F first
#define S second
const long long INF = 1LL << 60;
const int MOD = 1000000007;
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }

long long gcd(long long a,long long b)
{
    if (a%b==0) return(b);
    else return(gcd(b,a%b));
}
 long long lcm(long long a,long long b){
 long long g = gcd(a,b);
 return a / g * b; 
 }
signed main(void){
    int t,a,b; cin>>t>>a>>b;
    t--;
    int x = t/a;
    int y = t/b;
    int z = t/lcm(a,b);
    cout<<x-z+y+1<<endl;
}