#include <bits/stdc++.h>
using namespace std;
#define INF 1<<30
#define endl '\n'
#define maxn 1000005
#define FASTIO ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
typedef long long ll;
const double PI = acos(-1.0);
const ll mod = 1e9 + 7;

inline void normal(ll &a) { a %= mod; (a < 0) && (a += mod); }
inline ll modMul(ll a, ll b) { a %= mod, b %= mod; normal(a), normal(b); return (a * b) % mod; }
inline ll modAdd(ll a, ll b) { a %= mod, b %= mod; normal(a), normal(b); return (a + b) % mod; }
inline ll modSub(ll a, ll b) { a %= mod, b %= mod; normal(a), normal(b); a -= b; normal(a); return a; }
inline ll modPow(ll b, ll p) { ll r = 1; while (p) { if (p & 1) r = modMul(r, b); b = modMul(b, b); p >>= 1; } return r; }
inline ll modInverse(ll a) { return modPow(a, mod - 2); }
inline ll modDiv(ll a, ll b) { return modMul(a, modInverse(b)); }


///**
template < typename F, typename S >
ostream& operator << ( ostream& os, const pair< F, S > & p ) {
	return os << "(" << p.first << ", " << p.second << ")";
}

template < typename T >
ostream &operator << ( ostream & os, const vector< T > &v ) {
	os << "{";
	for (auto it = v.begin(); it != v.end(); ++it) {
		if ( it != v.begin() ) os << ", ";
		os << *it;
	}
	return os << "}";
}

template < typename T >
ostream &operator << ( ostream & os, const set< T > &v ) {
	os << "[";
	for (auto it = v.begin(); it != v.end(); ++it) {
		if ( it != v.begin()) os << ", ";
		os << *it;
	}
	return os << "]";
}

template < typename F, typename S >
ostream &operator << ( ostream & os, const map< F, S > &v ) {
	os << "[";
	for (auto it = v.begin(); it != v.end(); ++it) {
		if ( it != v.begin() ) os << ", ";
		os << it -> first << " = " << it -> second ;
	}
	return os << "]";
}

#define dbg(args...) do {cerr << #args << " : "; faltu(args); } while(0)

clock_t tStart = clock();
#define timeStamp dbg("Execution Time: ", (double)(clock() - tStart)/CLOCKS_PER_SEC)

void faltu () { cerr << endl; }

template <typename T>
void faltu( T a[], int n ) {
	for (int i = 0; i < n; ++i) cerr << a[i] << ' ';
	cerr << endl;
}

template <typename T, typename ... hello>
void faltu( T arg, const hello &... rest) { cerr << arg << ' '; faltu(rest...); }
// Program showing a policy-based data structure.
#include <ext/pb_ds/assoc_container.hpp> // Common file 
#include <ext/pb_ds/tree_policy.hpp>
#include <functional> // for less 
#include <iostream>
using namespace __gnu_pbds;
using namespace std;
// GNU link : https://goo.gl/WVDL6g
typedef tree<int, null_type, less_equal<int>, rb_tree_tag,
        tree_order_statistics_node_update>
        new_data_set;

// find_by_order(k) – ফাংশনটি kth ordered element এর একটা পয়েন্টার রিটার্ন করে। অর্থাৎ তুমি চাইলেই kth ইন্ডেক্সে কি আছে, সেটা জেনে ফেলতে পারছো!
// order_of_key(x) – ফাংশনটি x এলিমেন্টটা কোন পজিশনে আছে সেটা বলে দেয়।

/**___________________________________________________**/

inline ll MOD(ll x, ll m = mod)
{
	ll y = x % m;
	return (y >= 0) ? y : y + m;
}

inline ll SUM(ll a, ll n)
{
	ll b = a + n - 1;
	ll ans = (a + b) * (b - a + 1);
	return ans / 2ll;
}

int main()
{
	FASTIO
	/*
#ifndef ONLINE_JUDGE
	freopen("in.txt", "r", stdin);
	freopen("out.txt", "w", stdout);
	freopen("error.txt", "w", stderr);
#endif
//*/
	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;
	}
	map<ll, ll> mp; // reminder
	vector<vector<pair<ll, ll > > > ranges;
	for (int i = 0; i <= n; i++) {
		ll sm_x = x * i;
		ll r = MOD(sm_x, d);
		if (mp.find(r) == mp.end()) {
			mp[r] = ranges.size();
			ranges.emplace_back();
		}
		r = mp[r];

		ll sm_d_first = SUM(0, i);
		ll sm_d_second = SUM(n - i, i);

		ranges[r].emplace_back(sm_x + sm_d_first * d, 0);
		ranges[r].emplace_back(sm_x + sm_d_second * d, 1);
	}

	for (int i = 0; i < (int)ranges.size(); i++) {
		sort(ranges[i].begin(), ranges[i].end());
	}

	ll ans = 0;
	for (int r = 0; r < (int)ranges.size(); r++) {
		ll last = 0;
		int cnt = 0;

		for (auto p : ranges[r]) {
			if (cnt == 0) last = p.first;
			cnt += (p.second == 0) ? 1 : -1;
			if (cnt == 0) ans += ((p.first - last) / d + 1);
		}
	}
	cout << ans << endl;
	return 0;
}

Measured memory_bytes: 28204