#include <bits/stdc++.h>
using namespace std;
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
 
#define ms(s, n) memset(s, n, sizeof(s))
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define FORd(i, a, b) for (int i = (a) - 1; i >= (b); --i)
#define FORall(it, a) for (__typeof((a).begin()) it = (a).begin(); it != (a).end(); it++)
#define sz(a) int((a).size())
#define present(t, x) (t.find(x) != t.end())
#define all(a) (a).begin(), (a).end()
#define uni(a) (a).erase(unique(all(a)), (a).end())
#define pb push_back
#define pf push_front
#define mp make_pair
#define fi first
#define se second
#define prec(n) fixed<<setprecision(n)
#define bit(n, i) (((n) >> (i)) & 1)
#define bitcount(n) __builtin_popcountll(n)
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pi;
typedef vector<int> vi;
typedef vector<pi> vii;
const int MOD = (int) 1e9 + 7;
const int FFTMOD = 119 << 23 | 1;
const int INF = (int) 1e9 + 23111992;
const ll LINF = (ll) 1e18 + 23111992;
const ld PI = acos((ld) -1);
const ld EPS = 1e-9;
inline ll gcd(ll a, ll b) {ll r; while (b) {r = a % b; a = b; b = r;} return a;}
inline ll lcm(ll a, ll b) {return a / gcd(a, b) * b;}
inline ll fpow(ll n, ll k, int p = MOD) {ll r = 1; for (; k; k >>= 1) {if (k & 1) r = r * n % p; n = n * n % p;} return r;}
template<class T> inline int chkmin(T& a, const T& val) {return val < a ? a = val, 1 : 0;}
template<class T> inline int chkmax(T& a, const T& val) {return a < val ? a = val, 1 : 0;}
inline ull isqrt(ull k) {ull r = sqrt(k) + 1; while (r * r > k) r--; return r;}
inline ll icbrt(ll k) {ll r = cbrt(k) + 1; while (r * r * r > k) r--; return r;}
inline void addmod(int& a, int val, int p = MOD) {if ((a = (a + val)) >= p) a -= p;}
inline void submod(int& a, int val, int p = MOD) {if ((a = (a - val)) < 0) a += p;}
inline int mult(int a, int b, int p = MOD) {return (ll) a * b % p;}
inline int inv(int a, int p = MOD) {return fpow(a, p - 2, p);}
inline int sign(ld x) {return x < -EPS ? -1 : x > +EPS;}
inline int sign(ld x, ld y) {return sign(x - y);}
mt19937 mt(chrono::high_resolution_clock::now().time_since_epoch().count());
inline int mrand() {return abs((int) mt());}
inline int mrand(int k) {return abs((int) mt()) % k;}
#define db(x) cerr << "[" << #x << ": " << (x) << "] ";
#define endln cerr << "\n";
 
void chemthan() {
    const int magic = 5000;
    vector<vi> dvs(magic);
    FOR(i, 1, sz(dvs)) {
        for (int j = i; j < sz(dvs); j += i) {
            dvs[j].pb(i);
        }
    }
    int w, h, d; cin >> w >> h >> d;
    vector<vi> g(magic, vi(magic));
    FOR(i, 0, magic) g[0][i] = g[i][0] = i;
    FOR(i, 1, magic) FOR(j, 1, magic) {
        if (i <= j) g[i][j] = g[i][j - i];
        else g[i][j] = g[i - j][j];
    }
 
    auto calc = [&] (int x, int y) {
        if (!x || !y) return x + y - 1;
        x = abs(x), y = abs(y);
        if (y < x) swap(x, y);
        y %= x;
        if (x < magic && y < magic) return g[x][y] - 1;
        return __gcd(x, y) - 1;
    };
 
    long long res = 0;
    FOR(it, 0, 2) {
        vi f(1e6);
        FOR(i, 0, sz(f)) f[i] = __gcd(i, w) - 1;
        FOR(i, 1, w) if (i + i <= w) {
            for (int j = 1; j < h && i * j <= d + d + w + h + h; j++) {
                int t = d + d + calc(j, w - i) + 1 - i * j;
                //(w - i) * k - gcd(w, |j - k|) - gcd(i, k) <= t
                int c = 1 + (i + i < w);
                int s = min(h - 1, t < 0 ? 0 : t / (w - i));
                res += c * s;
                for (int k = s + 1; k < h; k++) {
                    if ((w - i) * k < t + w + i) {
                        if ((w - i) * k - f[abs(j - k)] - calc(i, k) <= t) {
                            res += c;
                        }
                    }
                    else {
                        break;
                    }
                }
            }
        }
        swap(w, h);
    }
    cout << res * 2 << "\n";
}

int main(int argc, char* argv[]) {
    ios_base::sync_with_stdio(0), cin.tie(0);
    if (argc > 1) {
        assert(freopen(argv[1], "r", stdin));
    }
    if (argc > 2) {
        assert(freopen(argv[2], "wb", stdout));
    }
    chemthan();
    cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
    return 0;
}


Measured memory_bytes: 105596