#include <bits/stdc++.h>

using namespace std;

using ll =  long long;
using Pll = pair<ll, ll>;
using Pii = pair<int, int>;

constexpr ll MOD = 1000000007;
constexpr long double EPS = 1e-10;
constexpr int dyx[4][2] = {
    { 0, 1}, {-1, 0}, {0,-1}, {1, 0}
};

ll gcd(ll a, ll b){
    if(b == 0) return a;
    else return gcd(b, a%b);
}

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

int main() {
    ios::sync_with_stdio(false); cin.tie(nullptr);
    ll t, a, b;
    cin >> t >> a >> b;
    ll l = lcm(a, b);

    ll ans = ((t-1)/a+1) + ((t-1)/b+1) - ((t-1)/l+1);
    cout << ans << endl;
}