#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(ll i = 0, i##_len = (n); i < i##_len; i++)
#define reps(i, s, n) for(ll i = (s), i##_len = (n); i < i##_len; i++)
#define rrep(i, n) for(ll i = (n) - 1; i >= 0; i--)
#define rreps(i, e, n) for(ll i = (n) - 1; i >= (e); i--)
#define all(x) (x).begin(), (x).end()
#define sz(x) ((ll)(x).size())
#define len(x) ((ll)(x).length())

ll mul(ll a, ll b) {
    ll inf = 2000000000000000000;
    if (b > (inf / a)) return inf;
    else return a * b;
}

ll gcd(ll a, ll b) {
    return b ? gcd(b, a % b) : a;
}

ll lcm(ll a, ll b) {
    return mul(a / gcd(a, b), b);
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    // ifstream in("input.txt");
    // cin.rdbuf(in.rdbuf());
    ll t, a, b;
    cin >> t >> a >> b;
    ll cnt1 = (t - 1) / a + 1;
    ll cnt2 = (t - 1) / b + 1;
    ll cnt3 = (t - 1) / lcm(a, b) + 1;
    ll ans = cnt1 + cnt2 - cnt3;
    cout << ans << endl;
    return 0;
}