#include <bits/stdc++.h>

using namespace std;

#define rep(i, n) for(int i = 0; i < (int)n; ++i)
#define FOR(i, a, b) for(int i = a; i < (int)b; ++i)
#define rrep(i, n) for(int i = ((int)n - 1); i >= 0; --i)

typedef long long ll;
typedef long double ld;

const int Inf = 1e9;
const double EPS = 1e-9;
const int MOD = 1e9 + 7;

template <typename T>
T gcd(T a, T b) {
    if (b == 0) {
        return a;
    } else {
        return gcd(b, a % b);
    }
}

template <typename T>
T lcm(T a, T b) {
    return a / gcd(a, b) * b;
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(0);
    ll t, a, b;
    cin >> t >> a >> b;
    ll res = 0;
    res += (t - 1) / a;
    res += (t - 1) / b;
    res++;
    res -= (t - 1) / a / (b / gcd(a, b));
    cout << res << endl;
    
    return 0;
}