#define _USE_MATH_DEFINES
#include  <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <string>
#include<math.h>
#include<iomanip>
#include<stdio.h>
#include <stdlib.h>
#include<stdio.h>
#include <queue>
#include<map>
#include <sstream>
#include<set>
#include<stack>

//#include<bits/stdc++.h>


using namespace std;

long long int gcd(long long int a, long long int b) {
	if (a == 0)return b;
	gcd(b%a, a);
}

int main() {

	
	long long int t, a, b;
	cin >> t >> a >> b;
	if (a > b)swap(a, b);

	long long int m = gcd(a, b);

	long long int x = (t-1) / a , y = (t-1) / b ;
	long long int z = x / (b/m);

	cout << x + y - z + 1 << endl;

	


	return 0;




}