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

signed main(){
  long long n,a,b;cin>>n>>a>>b;
  long long ga=a,gb=b;
  while(1){
  	if(ga<gb)swap(ga,gb);
  	if(ga%gb==0)break;
  	ga%=gb;
  }
  cout<<n-(n/a)-(n/b)+(n/(a*b/gb));
}