#include <bits/stdc++.h>

using namespace std;

#define int long long
// #define double long double
#define FOR(i, a, b) for(int i = (a); i < (b); ++i)
#define FORR(i, a, b) for(int i = (a); i > (b); --i)
#define REP(i, n) for(int i = 0; i < (n); ++i)
#define REPR(i, n) for(int i = n; i >= 0; i--)
#define FOREACH(x, a) for(auto &(x) : (a))
#define VECCIN(x)                                                              \
    for(auto &youso_ : (x)) cin >> youso_
#define bitcnt(x) __builtin_popcount(x)
#define lbit(x) __builtin_ffsll(x)
#define rbit(x) __builtin_clzll(x)
#define fi first
#define se second
#define All(a) (a).begin(), (a).end()
#define rAll(a) (a).rbegin(), (a).rend()
#define cinfast() cin.tie(0), ios::sync_with_stdio(false)
#define PERM(c)                                                                \
    sort(All(c));                                                              \
    for(bool cp = true; cp; cp = next_permutation(All(c)))
#define MKORDER(n)                                                             \
    vector<int> od(n);                                                         \
    iota(All(od), 0LL);

template <typename T = long long> inline T IN() {
    T x;
    cin >> x;
    return (x);
}
inline void CIN() {}
template <class Head, class... Tail>
inline void CIN(Head &&head, Tail &&... tail) {
    cin >> head;
    CIN(move(tail)...);
}
#define CCIN(...)                                                              \
    char __VA_ARGS__;                                                          \
    CIN(__VA_ARGS__)
#define DCIN(...)                                                              \
    double __VA_ARGS__;                                                        \
    CIN(__VA_ARGS__)
#define LCIN(...)                                                              \
    long long __VA_ARGS__;                                                     \
    CIN(__VA_ARGS__)
#define SCIN(...)                                                              \
    string __VA_ARGS__;                                                        \
    CIN(__VA_ARGS__)
#define Printv(v)                                                              \
    {                                                                          \
        FOREACH(x, v) { cout << x << " "; }                                    \
        cout << "\n";                                                          \
    }
template <typename T = string> inline void eputs(T s) {
    cout << s << "\n";
    exit(0);
}
template <typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val) {
    std::fill((T *)array, (T *)(array + N), val);
}

// generic lambdas
template <typename F>
#if defined(__has_cpp_attribute) && __has_cpp_attribute(nodiscard)
[[nodiscard]]
#elif defined(__GNUC__) &&                                                     \
    (__GNUC__ > 3 || __GNUC__ == 3 && __GNUC_MINOR__ >= 4)
__attribute__((warn_unused_result))
#endif // defined(__has_cpp_attribute) && __has_cpp_attribute(nodiscard)
    static inline constexpr decltype(auto)
    fix(F &&f) noexcept {
    return [f = std::forward<F>(f)](auto &&... args) {
        return f(f, std::forward<decltype(args)>(args)...);
    };
}

template <typename T> using PQG = priority_queue<T, vector<T>, greater<T>>;
template <typename T> using PQ = priority_queue<T>;

typedef long long ll;
typedef vector<ll> VL;
typedef vector<VL> VVL;
typedef pair<ll, ll> PL;
typedef vector<PL> VPL;
typedef vector<bool> VB;
typedef vector<double> VD;
typedef vector<string> VS;

const int INF = 1e9;
const int MOD = 1e9 + 7;
// const int MOD = 998244353;
const ll LINF = 1e18;
const double PI = atan(1.0) * 4.0;
const ll dw[] = {1, 1, 0, -1, -1, -1, 0, 1};
const ll dh[] = {0, 1, 1, 1, 0, -1, -1, -1};
#define PI 3.141592653589793238

struct SectionStructure {
    set<pair<ll, ll>> buf;
    SectionStructure() {
        buf.insert({-LINF, -LINF});
        buf.insert({LINF, LINF});
    }
    void add(ll l, ll r) {
        auto ite = buf.lower_bound({l, -LINF});

        if(ite->first == LINF) { // 大きいやつが無い
            ite--;
            if(ite->second <= l) { // 被ってないなら追加
                buf.insert({l, r});
            } else { // 被ってるならそれとくっつける
                ll L = ite->first;
                ll R = ite->second;

                buf.erase(ite);
                buf.insert({L, max(r, R)});
            }
        } else { // 被ってるのがある
            auto pre = buf.upper_bound({r, -LINF});
            auto pp = pre;
            pp--;

            ll L = min(l, ite->first);
            ll R = max(r, pp->second);

            ite--;
            if(ite->second <= l) { // 被ってないなら追加
                ite++;
            } else { // 被ってるならそれとくっつける
                L = ite->first;
            }

            buf.erase(ite, pre);
            buf.insert({L, R});
        }
    }
    set<pair<ll, ll>>::iterator get(ll x) {
        auto ite = buf.lower_bound({x, -LINF});

        if(ite->first == LINF) return buf.end();
        if(ite->second < x) return buf.end();
        return ite;
    }
    set<pair<ll, ll>>::iterator end() { return buf.end(); }
    int check(ll a, ll b) {
        if(a > b) swap(a, b);
        auto aa = buf.upper_bound({a, LINF});
        aa--;
        if(aa->first == -LINF) return false;
        return b <= aa->second;
    }
    void print() {
        printf("<>\n");
        for(auto p : buf) printf("[%lld,%lld]\n", p.first, p.second);
    }
};

signed main() {
    LCIN(N, X, D);
    // exception
    if(D == 0) eputs((X == 0 ? 1 : N + 1));
    // constraint
    if(D < 0) {
        D *= -1;
        X *= -1;
    }
    map<ll, VPL> sss;
    // num-bind
    REP(i, N + 1) {
        // bind this
        ll cnst = (X * i % D + D) % D;
        // width
        ll l = X * i / D + (i - 1) * i / 2;
        ll r = X * i / D + ((N - 1) + (N - i)) * i / 2;
        sss[cnst].emplace_back(l, r + 1);
    }
    ll ans = 0;
    FOREACH(ss, sss) {
        sort(All(ss.se));
        auto lr = *ss.se.begin();
        FOREACH(s, ss.se) {
            if(s.fi >= lr.se) {
                ans += lr.se - lr.fi;
                lr = s;
            } else {
                lr.se = max(lr.se, s.se);
            }
        }
        ans += lr.se - lr.fi;
    }
    cout << ans << "\n";
}

Measured memory_bytes: 22144