#include "bits/stdc++.h"
#define ALL(obj) (obj).begin(),(obj).end()
#define RALL(obj) (obj).rbegin(),(obj).rend()
#define REP(i, n) for(int i = 0; i < int(n); i++)
#define FOR(i,n,m) for(int i = int(n); i < int(m); i++)
using namespace std;
typedef long long ll;
const int MOD = 1e9 + 7;
const int INF = MOD - 1;
const ll LLINF = 4e18;

//gcd
template<typename T>
T gcd(T a, T b) {
    return b ? gcd(b, a%b) : a;
}

int main() {
    ll t, a, b; cin >> t >> a >> b;
    t--;
    if (a / gcd(a, b) > t / b) {
        cout << t / a + t / b + 1 << endl;
    }
    else {
        ll lcm = a / gcd(a, b) * b;
        cout << t / a - t / lcm + t / b + 1 << endl;
    }
}