#include <bits/stdc++.h>
using namespace std;
const auto start_time = std::chrono::high_resolution_clock::now();
void timecalculater(){
    #ifndef ONLINE_JUDGE
    auto end_time = std::chrono::high_resolution_clock::now();
    std::chrono::duration<double> diff = end_time-start_time;
    cerr<<"Time Taken : "<<diff.count()<<"\n";
    #endif
}
void __print(int x) {cout << x;}
void __print(long x) {cout << x;}
void __print(long long x) {cout << x;}
void __print(unsigned x) {cout << x;}
void __print(unsigned long x) {cout << x;}
void __print(unsigned long long x) {cout << x;}
void __print(float x) {cout << x;}
void __print(double x) {cout << x;}
void __print(long double x) {cout << x;}
void __print(char x) {cout << '\'' << x << '\'';}
void __print(const char *x) {cout << '\"' << x << '\"';}
void __print(const string &x) {cout << '\"' << x << '\"';}
void __print(bool x) {cout << (x ? "true" : "false");}
template<typename T, typename V>
void __print(const pair<T, V> &x) {cout << '{'; __print(x.first); cout << ','; __print(x.second); cout << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cout << '{'; for (auto &i: x) cout << (f++ ? "," : ""), __print(i); cout << "}";}
void _print() {cout << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cout << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define dbg(x...) cout << "[" << #x << "] = ["; _print(x)
#else
#define dbg(x...)
#endif
#define rep(i, n) for(int i = 0; i < (n); ++i)
#define repA(i, a, n) for(int  i = a; i <= (n); ++i)
#define all(x) x.begin(), x.end()
#define sz(x) (int) (x).size()
#define fill(a) memset(a, 0, sizeof(a))
#define fst first
#define snd second
#define mp make_pair
#define pb push_back
#define endl '\n'
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<long long int> vll;
typedef vector<pii> vii;
ll p=1e9+7;
const int N=2e5+5;
int main() {
   
    cin.sync_with_stdio(0); cin.tie(0);
    cin.exceptions(cin.failbit);
    int T=1;
    // cin>>T;
    while(T--){
        ll n,x,d;cin>>n>>x>>d;ll ans=0;
        map<ll,vector<pll>  > m;
        if(d==0){
            if(x==0){
                cout<<1;return 0;
            }
            else{
                cout<<(n+1);return 0;
            }
        }
        if(x==0){
            ll u=1+n*(n-1)/2;
            cout<<(u);return 0;
        }
        // d=-d;
        for(ll i=0;i<=n;i++){
            ll lo,hi;
            lo=i*x+d*(i*(i-1))/2;
            ll k=i*n-(i*(i+1)/2);
            hi=i*x+d*k;
            ll r=(i*x)%d;if(r<0)r=r+d;
            m[r].pb({min(lo,hi),max(lo,hi)});
            // dbg(r,lo,hi);
        }
        for(auto &v: m){
            sort(all(v.snd));
            ll temp=0;
            ll f=-1,l=-1;
            for(int i=0;i<v.snd.size();i++){
                if(l==-1||v.snd[i].fst>l){

                    if(l!=-1)
                    temp+=((l-f)/(abs(d))+1);
                    f=v.snd[i].fst;
                    l=v.snd[i].snd;
                    // dbg(l,f);
                }
                else{
                    l=max(l,v.snd[i].snd);
                }
            }
            if(l!=-1)
            temp+=((l-f)/(abs(d))+1);
            // dbg(l,f);
            // dbg(temp);
            ans+=temp;
        }
        cout<<ans<<endl;
    }   
    timecalculater();
    return 0;   
} 

Measured memory_bytes: 22144