#include<iostream>
#include<string>
#include<iomanip>
#include<cmath>
#include<vector>
#include<algorithm>

using namespace std;

// #define int long long
#define int __int128
#define endl "\n"

const long long INF = (long long)1e18;
const long long MOD = 1'000'000'007; 

string yn(bool f){return f?"Yes":"No";}
string YN(bool f){return f?"YES":"NO";}



signed main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(10);
	
	long long T, A, B, lcm = INF*2;
	int a, b, l;
	cin>>T>>A>>B;
	T--;
	
	if((T+B-1)/B > A/__gcd(A,B))lcm = (unsigned __int128)A/__gcd(A,B) * B;
	
	// cout<<T/A<<" "<<T/B<<" "<<T/lcm<<endl;
	
	a = T/A;
	b = T/B;
	l = T/lcm;
	
	// cout<<(long long)a<<" "<<(long long)b<<" "<<(long long)l<<endl;
	// a = (T+A-1)/A;
	// b = (T+B-1)/B;
	// l = (T+lcm-1)/lcm;
	
	// if(T%A) a++;
	// if(T%B) b++;
	// if(T%lcm) l++;
	
	// cout<<T/A + T/B - T/lcm<<endl;
	cout<<(unsigned long long)(a+b-l)+1<<endl;
	
	return 0;
}