#include<iostream>
#include<bits/stdc++.h>

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define rep_r(i, n) for(int i = n-1; i >= 0; i--)
#define rep1(i, n) for(int i = 1; i <= (int)(n); i++)
#define REP(i,n) for(int i=0, i##_len=(n); i<i##_len; ++i)
#define all(x) (x).begin(),(x).end()
#define SZ(x) ((ll)(x).size())
#define bit(n) (1LL<<(n))
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );

#define INF bit(60)
#define pb push_back
#define mod 1000000007

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

using namespace std;
using uif=uint_fast64_t;
using ll=long long int;
using tTree=__gnu_pbds::tree< ll , __gnu_pbds::null_type, less< ll >, __gnu_pbds::rb_tree_tag, __gnu_pbds::tree_order_statistics_node_update>;

int qp(int a,ll b){int ans=1;do{if(b&1)ans=1ll*ans*a%mod;a=1ll*a*a%mod;}while(b>>=1);return ans;}
int qp(int a,ll b,int mo){int ans=1;do{if(b&1)ans=1ll*ans*a%mo;a=1ll*a*a%mo;}while(b>>=1);return ans;}

int gcd(int a,int b){return b?gcd(b,a%b):a;}
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};


#define FACSIZE 2002

ll invfac[FACSIZE];
ll fac[FACSIZE];

ll mod_pow(ll ,ll );
ll mod_add(ll ,ll );
ll mod_mul(ll ,ll );
ll mod_div(ll ,ll );
void make_fact(ll );
void make_invfact(ll );



int main(void){

  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+(n-1)*d;
    d=-d;
  }

  using pa=pair<ll,ll>;
  unordered_map<ll,vector<pa>> um;  

  for( ll i=0;i<=n;i++ ){
    ll sL,sR;
    if(i==0){
      sL=0,sR=0;
    }
    else{
      sL=i*x + i*(i-1)*d/2 ;
      sR=i*x + i*( n-1 + n-i )*d/2 ;

      

    }
    ll mo=(i*x)%d;
    um[ mo ].push_back(make_pair( (sL-mo)/d  , (sR-mo)/d ));
  }
  ll ans=0;
  for(auto p:um){
    //cout << p.first << endl;
    stack<ll> sta;
    //sta.clear();
    priority_queue<pa,vector<pa>,greater<pa>> pque;
    //pque.clear();
    vector<pa> vec;
    vec.clear();
    for(auto x:p.second){
      //cout << x.first << "," << x.second << endl;
      pque.push(make_pair(x.first,1));
      pque.push(make_pair(x.second,2));
    }
    //cout << endl;
    
    while(!pque.empty()){

      auto pq=pque.top();
      pque.pop();
      if(pq.second==1){
        sta.push( pq.first );
      }
      else{
        ll val=sta.top();
        sta.pop();
        if(sta.empty()){
          vec.push_back( make_pair(val,pq.first ));
        }
      }

    }
    for(auto x:vec){
      //cout << x.first << ","<< x.second << endl;
      ans+= x.second - x.first + 1;
    }

  }

  cout << ans << endl;

  return 0;

}

ll mod_pow(ll x,ll r){
  if(r==0) return 1;
  else if(r==1) return x%mod;
  else if(r%2==0){
    ll t=mod_pow(x,r/2)%mod;
    return t*t %mod;
  } 
  else{
    ll t=mod_pow(x,r/2)%mod;
    ll k= t*t %mod;
    return k*x%mod;
  } 
}
ll mod_add(ll a,ll b){
  return (a+b)%mod;
}

ll mod_mul(ll a,ll b){
  return (a*b)%mod;
}

ll mod_div(ll a,ll b){
  return mod_mul(a,mod_pow(b,mod-2));
}

void make_fact(ll n){
  fac[0]=1;
  rep(i,n){
    fac[i+1]=mod_mul(fac[i],i+1);
  }  
}

void make_invfact(ll n){
  invfac[n]= mod_pow( fac[n] ,mod-2);
  for(int i=n-1;i>=0;i--){
    invfac[i]=mod_mul(invfac[i+1],i+1);
  }

}


Measured memory_bytes: 17864