#include <bits/stdc++.h>
using namespace std;

#define REP(i, n) for(ll (i) = 0; (i) < (n); (i)++)
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define MIN(a, b) ((a) < (b) ? (a) : (b))

typedef long long ll;

ll gcm(ll a, ll b){
	if(!b) return a;
	else return (b, a%b);
}

int main(void){
	ll t, a, b;
	cin >> t >> a >> b;

	if(a < b) swap(a, b);

	ll lcm = a/gcm(a, b)*b;
	ll ans = (t-1)/a+1+(t-1)/b+1-((t-1)/lcm+1);

	cout << ans << endl;

	return 0;
}