#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <atcoder/modint>

using namespace std;
using i32 = int32_t;
using u32 = uint32_t;
using i64 = int64_t;
using u64 = uint64_t;
#define rep(i,n) for(int i=0; i<(int)(n); i++)


const i64 INF = 1001001001001001001;
using modint = atcoder::static_modint<998244353>;

int main(){
    i64 A, B, S; cin >> A >> B >> S;
    i64 ans = 0;
    for(i64 h=1; h<=A; h++) for(i64 w=1; w<=B && w*h<=S; w++) ans += (A-h+1) * (B-w+1);
    cout << ans << endl;
    return 0;
}


struct ios_do_not_sync{
    ios_do_not_sync(){
        std::ios::sync_with_stdio(false);
        std::cin.tie(nullptr);
    }
} ios_do_not_sync_instance;