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

#define REP(i, m, n) for (int i = (m); i < (int)(n); i++)
#define REPS(i, m, n) for (int i = (m); i <= (int)(n); i++)
#define rep(i, n) REP(i, 0, n)
#define reps(i, n) for (int i = 0; i <= (int)(n); i++)
#define rrep(i, x) for (int i = ((int)(x)-1); i >= 0; i--)
#define rreps(i, x) for (int i = (int)(x); i >= 0; i--)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define pb push_back
typedef long long ll;
typedef pair<int, int> P;
const int inf = INT_MAX;
const ll INF = 1LL << 60;
const ll mod = 1e9 + 7;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<typename A, size_t N, typename T> void Fill(A (&array)[N], const T &val) { fill( (T*)array, (T*)(array+N), val ); }

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

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

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    ll T, A, B; cin >> T >> A >> B;
    T--;
    ll a = T / A;
    ll b = T / B;
    ll p = gcd(A, B);
    ll g, d = 0;
    if (log10(A / p) + log10(B / p) >= 18) {
        g = T;
        d = 1;
    } else {
        g = lcm(A, B);
    }
    cout << a + b - (T / g) + 1 + d << endl;
    return 0;
}