#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <tuple>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <cmath>
#include <iomanip>
#define rep(i, n) for(int i = 0; i < (int)(n); ++i)
using namespace std;

long long GCD(long long A, long long B) {if (A % B) return GCD(B, A % B); return B;}
long long LCM(long long A, long long B) {return A / GCD(A, B) * B;}

int main() {
    long long T, A, B;
    cin >> T >> A >> B;
    cout << (T + A - 1) / A + (T + B - 1) / B - (T + LCM(A, B) - 1) / LCM(A, B) << endl;
}