#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#define popcount __builtin_popcount
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
typedef __int128_t lll;
ll gcd(ll a, ll b){
	if(b==0) return a;
	return gcd(b, a%b);
}
lll lcm(lll a, lll b){
	return a/gcd(a, b)*b;
}
int main()
{
	ll t, a, b; cin>>t>>a>>b;
	lll l=lcm(a, b);
	ll ans=(t+a-1)/a+(t+b-1)/b-(t+l-1)/l;
	cout<<ans<<endl;
	return 0;
}