#include "bits/stdc++.h"
using namespace std;
using ll     = long long;
using pii    = pair<int, int>;
using pll    = pair<ll, ll>;
using vi     = vector<int>;
using vl     = vector<ll>;
using vvi    = vector<vi>;
using vvl    = vector<vl>;
const ll INF = 1LL << 60;
const ll MOD = 1000000007;
template <class T>
bool chmax(T &a, const T &b) {
    return (a < b) ? (a = b, 1) : 0;
}
template <class T>
bool chmin(T &a, const T &b) {
    return (b < a) ? (a = b, 1) : 0;
}
template <class C>
void print(const C &c, std::ostream &os = std::cout) {
    std::copy(std::begin(c), std::end(c), std::ostream_iterator<typename C::value_type>(os, " "));
    os << std::endl;
}

// greatest common divisor and least common multiple
// gcd is calculated by Euclidean Algorithm
// lcm = m * n / gcd(m,n)
template <typename T = int>
T gcd(T a, T b) {
    if (a < b)
        return gcd(b, a);
    T r;
    while ((r = a % b)) {
        a = b;
        b = r;
    }
    return b;
}

template <typename T = int>
T lcm(T m, T n) {
    if ((0 == m) || (0 == n))
        return 0;
    return ((m / gcd(m, n)) * n);
}

int main() {
    ll t, a, b;
    cin >> t >> a >> b;
    ll ret = 0;
    ret += (t + a - 1) / a;
    ret += (t + b - 1) / b;
    ll c = lcm(a, b);
    ret -= (t + c - 1) / c;
    cout << ret << "\n";
    return 0;
}