/* Aa^~ kokoro ga pyonpyon suru n jaa^~
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// MMMMM#<<_jwr:(Z4QHHMMHMHHHHHHHHHHHHHHHHHHHHHHHHHHHH###NHSXZ>` ~````.OXtt>~._<?MM
*/
#include<bits/stdc++.h>
using namespace std;
#ifndef ONLINE_JUDGE
#define dbg(x...) do { cout << "\033[32;1m " << #x << " -> "; err(x); } while (0)
void err() { cout << "\033[39;0m" << endl; }
template<template<typename...> class T, typename t, typename... A>
void err(T<t> a, A... x) { for (auto v: a) cout << v << ' '; err(x...); }
template<typename T, typename... A>
void err(T a, A... x) { cout << a << ' '; err(x...); }
#else
#define dbg(...)
#endif
typedef long long ll;
typedef pair<ll,ll> pi;
typedef vector<int> vi;
template<class T> using vc=vector<T>;
template<class T> using vvc=vc<vc<T>>;
template<class T> void mkuni(vector<T>&v)
{
    sort(v.begin(),v.end());
    v.erase(unique(v.begin(),v.end()),v.end());
}
ll rand_int(ll l, ll r) //[l, r]
{
    static mt19937_64 gen(chrono::steady_clock::now().time_since_epoch().count());
    return uniform_int_distribution<ll>(l, r)(gen);
}
template<class T>
void print(T x,int suc=1)
{
    cout<<x;
    if(suc==1) cout<<'\n';
    else cout<<' ';
}
template<class T>
void print(const vector<T>&v,int suc=1)
{
    for(int i=0;i<v.size();i++)
    print(v[i],i==(int)(v.size())-1?suc:2);
}
struct D{
    int rem;
    ll l,r;
    bool operator<(const D&a)const{
        if(rem==a.rem) return l<a.l;
        return rem<a.rem;
    }
};
int main()
{
    int n,x,d;
    cin>>n>>x>>d;
    if(d==0)
    {
        if(x==0) print(1);
        else{
            print(n+1);
        }
        return 0;
    }
    if(d<0)
    {
        d=-d;
        x=-x;
    }
    vc<D> seg(n+1);
    for(int i=0;i<=n;i++)
    {
        ll cur=(ll)i*x;
        ll up=cur+(ll)(n-1+n-i)*i/2*d;
        ll down=cur+(ll)i*(i-1)/2*d;
        //dbg(i,up,down);
        seg[i]={(int)(cur%d),down,up};
    }
    sort(seg.begin(),seg.end());
    ll ans=0;
    ans=((seg[0].r-seg[0].l)/d+1);
    ll prer=seg[0].r;
    for(int i=1;i<=n;i++)
    {
        if(seg[i].rem==seg[i-1].rem)
        {
            if(seg[i].l<=prer)
                ans+=max(0LL,(seg[i].r-prer)/d);
            else ans+=(seg[i].r-seg[i].l)/d+1;
            prer=max(prer,seg[i].r);
        }
        else{
            ans+=(seg[i].r-seg[i].l)/d+1;
            prer=seg[i].r;
        }
    }
    print(ans);

}

Measured memory_bytes: 4992