#include <bits/stdc++.h>
#include <atcoder/all>

using namespace std;
using namespace atcoder;

using ll = long long;
typedef pair<ll,ll> P;
#define SORT(a) sort((a).begin(),(a).end())
#define REV(a) reverse((a).begin(),(a).end())
#define For(i, a, b)    for(ll i = (a) ; i < (b) ; ++i)
#define rep(i, n)       For(i, 0, n)
#define debug(x)  cerr << #x << " = " << (x) << endl;
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }

void coY() {cout <<"Yes"<<endl;}
void coN(){cout <<"No"<<endl;}
void coT() {cout <<"Takahashi"<<endl;}
void coA(){cout <<"Aoki"<<endl;}

void mswap(ll &a, ll &b){ if(a >= b) swap(a,b); }
void rswap(ll &a, ll &b){ if(a <= b) swap(a,b); }

const ll dy[] = {0,0,1,-1};
const ll dx[] = {1,-1,0,0};
const ll mod = 1e9+7;
const ll MOD = 998244353;
using mint = modint998244353;
const double PI=3.14159265358979323846;
const ll inf = 1001001001;
const ll INF = 9'000'000'000'000'000'000;

vector<ll> to[200'005];
//Write From this Line
int main()
{
	ll H, W, S;
	cin >> H>> W>> S;
	ll ans = 0;
	for(ll h = 1; h <= S; h++){
		ll w = 1;
		while(h*w <= S){
			// h * wの枕はnanko??
			ll tate = (H-h+1);
			ll yoko = (W-w+1);
			if(tate >= 0 && yoko >=0){
				ll now = tate * yoko;
				ans += now;
			}
			w += 1;
		}
	}
	cout << ans << endl;
}