#ifdef LOCAL
#define _GLIBCXX_DEBUG
#endif
#include<bits/stdc++.h>
using namespace std;
#define rep(i,s,t) for(ll i = (ll)(s); i < (ll)(t); i++)
#define rrep(i,s,t) for(ll i = (ll)(s-1);(ll)(t) <= i; i--)
#define all(x) (x).begin(), (x).end()
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> Pll;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
constexpr ll INF = numeric_limits<ll>::max()/4;
constexpr ll n_max = 2e5+10;
#define int ll

template <typename A, typename B>
string to_string(pair<A, B> p);
string to_string(const string &s) {return '"' + s + '"';}
string to_string(const char *c) {return to_string((string) c);}
string to_string(bool b) {return (b ? "true" : "false");}
template <size_t N>
string to_string(bitset<N> v){
    string res = "";
    for(size_t i = 0; i < N; i++) res += static_cast<char>('0' + v[i]);
    return res;
}
template <typename A>
string to_string(A v) {
    bool first = true;
    string res = "{";
    for(const auto &x : v) {
        if(!first) res += ", ";
        first = false;
        res += to_string(x);
    }
    res += "}";
    return res;
}
template <typename A, typename B>
string to_string(pair<A, B> p){return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";}

void debug_out() {cerr << endl;}
template<typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << " " << to_string(H);
    debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

template<class T>
bool chmax(T &a, T b){if(a < b){a = b; return true;} return false;}
template<class T>
bool chmin(T &a, T b){if(a > b){a = b; return true;} return false;}

signed main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    ll n,x,d; cin >> n >> x >> d;
    if(d == 0){
        if(x)cout << n + 1 << endl;
        else cout << 1 << endl;
        return 0;
    }
    map<ll, set<Pll>> mp;
    ll min_, max_;
    rep(i,0,n+1){
        min_ = x * i + d * (i * (i-1) / 2);
        max_ = x * i + d * ((2 * n - i - 1) * i / 2);
        debug(min_, max_);
        max_ += d;
        if(min_ > max_)swap(min_, max_);
        debug(min_, max_);
        ll m = min_ % d;
        if(m < 0)m += d;
        if(mp[m].empty()){
            mp[m].insert({min_, max_});
            continue;
        }
        auto itr = mp[m].lower_bound({min_, -INF});
        ll e = min_;
        if(itr != mp[m].begin()){
            itr--;
            if(itr->second >= min_){
                min_ = itr->first;
                e = itr->second;
                auto itr2 = itr;
                itr++;
                mp[m].erase(itr2);
            }
            else itr++;
        }
        bool is_end = false;
        while(e < max_){
            if(itr == mp[m].end()){
                is_end = true;
                break;
            }
            if(itr->first > max_){
                e = max_;
                break;
            }
            e = itr->second;
            auto itr2 = itr;
            itr++;
            mp[m].erase(itr2);
        }

        if(is_end){
            e = max_;
        }
        
        mp[m].insert({min_, e});
    }

    ll ans = 0;
    for(auto &st : mp){
        debug(st.first);
        for(auto &p : st.second){
            debug(p);
            ans += (p.second - p.first) / abs(d);
        }
    }

    cout << ans << endl;
}

Measured memory_bytes: 34848