#include<bits/stdc++.h>
//ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
//clock_t start=clock();clock_t end=clock();cout<<(double)(end-start)/CLOCKS_PER_SEC<<endl;
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int ui;
typedef pair<int,int> pii;
typedef pair<pii,int> ppii;
typedef pair<int,pii> pipi;
typedef pair<ll,ll> pll;
typedef pair<pll,ll> ppll;
typedef pair<ll,pll> plpl;
typedef tuple<ll,ll,ll> tl;
typedef pair<double,double> pdd;
ll mod=1000000007;
ll mod2=998244353;
ll mod3=1000003;
ll mod4=998244853;
ll mod5=1000000009;
ll inf=1LL<<60;
double pi=3.141592653589793238462643383279L;
double eps=1e-9;
#define rep(i,m,n) for(int i=m;i<n;i++)
#define rrep(i,n,m) for(int i=n;i>=m;i--)
#define srep(itr,st) for(auto itr=st.begin();itr!=st.end();itr++)
#define Max(a,b) a=max(a,b)
#define Min(a,b) a=min(a,b)
int dh[4]={1,-1,0,0};
int dw[4]={0,0,1,-1};
int ddh[8]={-1,-1,-1,0,0,1,1,1};
int ddw[8]={-1,0,1,-1,1,-1,0,1};
ll gcd(ll a,ll b){
    if(a<b)swap(a,b);
    if(b==0)return a;
    if(a%b==0)return b;
    return gcd(b,a%b);
}
ll Pow(ll n,ll k){
    ll ret=1;
    ll now=n;
    while(k>0){
        if(k&1)ret*=now;
        now*=now;
        k/=2;
    }
    return ret;
}
ll beki(ll n,ll k,ll md){
  ll ret=1;
  ll now=n;
  while(k>0){
    if(k%2==1){
      ret*=now;
      ret%=md;
    }
    now*=now;
    now%=md;
    k/=2;
  }
  return ret;
}
ll gyaku(ll n,ll md){
  return beki(n,md-2,md);
}
ll popcount(ll n){
    ll ret=0;
    ll u=n;
    while(u>0){
        ret+=u%2;
        u/=2;
        
    }
    return ret;
}
int main(){
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    //cout<<7/(-2)<<" "<<7%(-2)<<endl;return 0;
    ll n,x,d;cin>>n>>x>>d;
    if(d==0){
        if(x==0)cout<<1<<endl;
        else cout<<n+1<<endl;
        return 0;
    }
    if(d<0){
        x=-x;
        d=-d;
    }
    map<ll,vector<pll>> mp;
    set<ll> st;
    ll el=0,er=0;
    rep(i,0,n+1){
        el+=i-1;
        er+=n-i;
        if(i==0){
            el=0;
            er=0;
        }
        ll sl=el*d+i*x+4000000000000000000,sr=er*d+i*x+4000000000000000000;
        ll r=sl%d;
        st.insert(r);
        sl/=d;sr/=d;
        if(sl>sr)swap(sl,sr);
        mp[r].push_back({sl,sr});
    }
    ll ans=0;
    /*for(auto e:mp[0]){
        cout<<e.first<<" "<<e.second<<endl;
    }*/
    srep(itr,st){
        ll now=*itr;
        sort(mp[now].begin(),mp[now].end());
        ll nr=mp[now][0].second,nl=mp[now][0].first;
        ans+=nr-nl+1;
        //cout<<nl<<" "<<nr<<" "<<mp[now][1].first<<" "<<mp[now][1].second<<endl;
        rep(i,1,mp[now].size()){
            //cout<<nr<<" "<<nl<<endl;
            //cout<<ans<<endl;
            ll nnr=mp[now][i].second,nnl=mp[now][i].first;
            //cout<<nnr<<" "<<nnl<<endl;
            if(nnl>nr){
                ans+=nnr-nnl+1;
                nl=nnl;
                nr=nnr;
            }
            else{
                if(nnr>nr){
                    ans+=nnr-nr;
                    nl=nnl;
                    nr=nnr;
                }
                else{
                    nl=nnl;
                }
            }
        }
        //cout<<ans<<endl;
    }
    cout<<ans<<endl;
}







Measured memory_bytes: 31488