#include<iostream>
#include<algorithm>
#include<vector>
#include<stack>
#include <cmath>
#include <limits>
#include<set>
#include <iomanip>
#include <queue>
#pragma GCC optimize("Ofast")
using namespace std;
const long long INF=20000000000;
//setprecision(2) <<

const int MOD = 1000000007;

long long max(long long a,long long b){
	if(a<b)return b;
	else return a;	
}
long long min(long long a,long long b){
	if(a>b)return b;
	else return a;	
}
long long gcd(long long a,long long b){
	if(a<b)swap(a,b);
	if(a%b==0)return b;
	else return gcd(a%b,b);
}

long long lcm(long long a,long long b){
	return a*b/gcd(a,b);
}


int main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	long long T,A,B;
	cin>>T>>A>>B;
	long long l=lcm(A,B);
	cout<<(T-1)/A + (T-1)/B -(T-1)/l+1<<endl;
}