#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream>
#include <random>
#include<map>
#include <iomanip>
#include <time.h>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
#include <cassert>
#include<fstream>
#include <unordered_map>
#include <cstdlib>
#include <complex>
#include <cctype>
#include <bitset>
using namespace std;
typedef string::const_iterator State;
#define Ma_PI 3.141592653589793
#define eps 1e-5
#define LONG_INF 1000000000000000000LL
#define GOLD 1.61803398874989484820458
#define MAX_MOD 1000000007LL
#define GYAKU 500000004LL
#define MOD 998244353LL
#define seg_size 262144*4
#define REP(a,b) for(long long a = 0;a < b;++a)
long long gcd(long long a, long long b) {
	if (b == 0) return a;
	return gcd(b, a % b);
}
int main() {
	long long t, a, b;
	cin >> t >> a >> b;
	long long ans = (t + a - 1LL) / a + (t + b - 1LL) / b - 1LL;
	long long get_gcd = gcd(a, b);
	if (t / b >= a / get_gcd) {
		long long syuuki = a * b / get_gcd;
		ans -= (t + syuuki - 1LL) / syuuki;
		ans++;
	}
	cout << ans << endl;
}