#include <bits/stdc++.h>
using namespace std;

#define all(v) (v).begin(),(v).end()
#define pb emplace_back
#define rep(i, n) for(int i=0;i<(n);i++)
#define foa(e, v) for(auto& e : v)
#define dout(a) cout<<fixed<<setprecision(10)<<a<<'\n';
#define Cout(a) cout<<a<<'\n';

using ll = long long;
using ld = long double;
using Int = __int128;
template <class T> using pqr = priority_queue<T, vector<T>, greater<T>>;

template <typename T1, typename T2> inline bool chmax(T1 &a, T2 b) {
    bool compare = a < b;
    if(compare) a = b;
    return compare;
}
template <typename T1, typename T2> inline bool chmin(T1 &a, T2 b) {
    bool compare = a > b;
    if(compare) a = b;
    return compare;
}
template <typename T> inline T back(std::set<T> &s) {
    return *s.rbegin();
}
template <typename T> inline T back(std::multiset<T> &s) {
    return *s.rbegin();
}
template <typename T> inline T pop_back(std::set<T> &s) {
    auto it = prev(s.end());
    T val = *it;
    s.erase(it); 
    return val;
}
template <typename T> inline T pop_back(std::multiset<T> &s) {
    auto it = prev(s.end());
    T val = *it;
    s.erase(it); 
    return val;
}

const int dy[8] = {-1, 0, 0, 1, 1, -1, 1, -1};
const int dx[8] = {0, -1, 1, 0, -1, -1, 1, 1};

const ll MOD7 = 1000000007, MOD998 = 998244353, INF = (3LL << 59);
const int inf = 1 << 30;
const char br = '\n';

// floor(sqrt(n))
long long sqrtll(long long n) { 
    // 3037000500 = ceil(sqrt(2^63))
    long long le = 0, ri = 3000000000; 
    while(ri - le > 1) {
        long long mid = (le + ri) / 2;
        if(mid * mid < n) le = mid;
        else ri = mid;
    }
    return ri;
}

ll calc1(ll a, ll b, ll c) {
    ll x = b * b - a * c * 2;
    ll y = sqrtll(x);
    b += y;
    b = 1LL - b;
    if(b % a == 0) return b / a;
    if(b >= 0) {
        return ((a + b - 1) / a);
    }
    return b / a;
}
ll calc2(ll a, ll b, ll c) {
    ll x = b * b - a * c * 2;
    ll y = sqrtll(x);
    b -= y;
    b = -b;
    b --;
    if(b % a == 0) return b / a;
    if(b >= 0) {
        return b / a;
    }
    return -((a - b - 1) / a);
}
void solve() {
    ll a, b, c; cin >> a >> b >> c;
    if(a < 0) {
        a = -a;
        b = -b;
        c = -c;
    }
    a *= 2;
    ll m1 = calc1(a, b, c);
    ll m2 = calc2(a, b, c);

    cout << m2 - m1 + 1 << endl;


}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int testcase = 1; 
    // cin >> testcase;
    while(testcase --) solve();

    return 0;
}