#include <bits/stdc++.h>
using namespace std;
int dx[] = {0, 0, 1, -1, -1, -1, 1, 1};
int dy[] = {1, -1, 0, 0, -1, 1, 1, -1};
template <class T>
inline T biton(T n, T pos) {
  return n | ((T)1 << pos);
}
template <class T>
inline T bitoff(T n, T pos) {
  return n & ~((T)1 << pos);
}
template <class T>
inline T ison(T n, T pos) {
  return (bool)(n & ((T)1 << pos));
}
template <class T>
inline T gcd(T a, T b) {
  while (b) {
    a %= b;
    swap(a, b);
  }
  return a;
}
template <typename T>
string NumberToString(T Number) {
  ostringstream second;
  second << Number;
  return second.str();
}
inline int nxt() {
  int aaa;
  scanf("%d", &aaa);
  return aaa;
}
inline long long int lxt() {
  long long int aaa;
  scanf("%lld", &aaa);
  return aaa;
}
inline double dxt() {
  double aaa;
  scanf("%lf", &aaa);
  return aaa;
}
template <class T>
inline T bigmod(T p, T e, T m) {
  T ret = 1;
  for (; e > 0; e >>= 1) {
    if (e & 1) ret = (ret * p) % m;
    p = (p * p) % m;
  }
  return (T)ret;
}
int ar[1000010];
long long F(long long int limit, long long int a, long long int b) {
  if (limit < a) return 1LL;
  long long int sum = 1LL;
  long long int x = 0;
  while (true) {
    if (x + a > limit) break;
    long long int temp = (limit - x) / a;
    sum += temp;
    long long int r = (a * temp) + x;
    if (r - b < 0) break;
    temp = (r + b - 1) / b;
    temp--;
    sum += temp;
    r -= temp * b;
    x = r;
    if (x % a == 0) break;
  }
  return sum;
}
long long int get(long long int st, long long int len) {
  long long int sum = (len * len + len) / 2LL;
  sum *= st;
  return sum;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  long long n, a, b;
  cin >> n >> a >> b;
  long long limit = min(a + b - 2, n);
  long long sum = 0;
  for (long long i = 0; i <= limit; i++) {
    sum += F(i, a, b);
  }
  limit++;
  long long int gc = gcd(a, b);
  while (limit <= n) {
    if (limit % gc == 0) break;
    sum += (limit / gc) + 1;
    limit++;
  }
  long long int upperLimit = n;
  while (upperLimit >= limit) {
    sum += (upperLimit / gc) + 1;
    if (upperLimit % gc == 0) break;
    upperLimit--;
  }
  if (upperLimit > limit) {
    long long int diff = (upperLimit - limit);
    sum += diff;
    diff /= gc;
    long long int chunk = limit * diff + get(gc, diff - 1);
    sum += chunk;
  }
  cout << sum << endl;
  return 0;
}
