#ifdef MAIN 
bool __multi__ = 0;
using INT = long long;

namespace XK {

  void solve() {
  	ll N, M; double P; rd(N, M, P);
  	if(N == 1 && M == 1) {
  		wt(P);
  	} else if(N == 1 || M == 1) {
  		if(N > M) swap(N, M);
  		double ans = 0.0f;
  		ans += 2 * P * P + (M - 2) * P * P * P;
  		wt(ans);
  	} else {
  		double ans = 0.0f;
  		ans += 4 * P * P * P;
  		ans += (2 * (N - 2) + 2 * (M - 2)) * P * P * P * P;
  		ans += (N - 2) * (M - 2) * P * P * P * P * P;
  		wt(ans);
  	}
  }
};

#else
#include "cassert"
#include "cmath"
#include "cstdint"
#include "cstdio"
#include "cstdlib"
#include "cstring"
#include "algorithm"
#include "bitset"
#include "chrono"
#include "complex"
#include "deque"
#include "functional"
#include "iostream"
#include "limits"
#include "map"
#include "numeric"
#include "queue"
#include "random"
#include "set"
#include "sstream"
#include "string"
#include "unordered_map"
#include "unordered_set"
#include "utility"
#include "vector"
#include "array"
using namespace std;
#define int long long
using ll = long long;
using ull = unsigned long long;
const ll INF = 1ll << 60;
const ll LINF = 0x1fffffffffffffff;
const ll MINF = 0x7fffffffffff;
template <class A, class B> bool chmax(A& l, const B& r){ return r > l ? l = r, 1 : 0; }
template <class A, class B> bool chmin(A& l, const B& r){ return r < l ? l = r, 1 : 0; }
#define sz(x) ssize(x)
#define rep(i, a) for(ll i = 0; i < (a); i ++)
#define Rep(i, a, b) for(ll i = (a); i < (b); i ++)
#define rrep(i, a, b) for(ll i = (b); i --> (a); )
#define all(x) begin(x), end(x)
template<class... Ts> void rd(Ts&... t);
[[maybe_unused]] void wtN(){}
template<class T, class... Ts> void wtN(const T& t, const Ts&... ts);
template<class... Ts> void wt(const Ts&... ts){ wtN(ts...); cout << '\n'; }
namespace IO{
    #define VOID(a) decltype(void(a))
    struct S{ S(){ cin.tie(nullptr)->sync_with_stdio(0); fixed(cout).precision(12); } }S;
    template<int I> struct P : P<I-1>{};
    template<> struct P<0>{};
    template<class T> void i(T& t){ i(t, P<3>{}); }
    void i(vector<bool>::reference t, P<3>){ int a; i(a); t = a; }
    template<class T> auto i(T& t, P<2>) -> VOID(cin >> t){ cin >> t; }
    template<class T> auto i(T& t, P<1>) -> VOID(begin(t)){ for(auto&& x : t) i(x); }
    template<class T, size_t... idx> void ituple(T& t, index_sequence<idx...>){ in(get<idx>(t)...); }
    template<class T> auto i(T& t, P<0>) -> VOID(tuple_size<T>{}){ ituple(t, make_index_sequence<tuple_size<T>::value>{}); }
    template<class T> void o(const T& t){ o(t, P<4>{}); }
    template<size_t N> void o(const char (&t)[N], P<4>){ cout << t; }
    template<class T, size_t N> void o(const T (&t)[N], P<3>){ o(t[0]); for(size_t i = 1; i < N; i++){ o(' '); o(t[i]); } }
    template<class T> auto o(const T& t, P<2>) -> VOID(cout << t){ cout << t; }
    template<class T> auto o(const T& t, P<1>) -> VOID(begin(t)){ bool first = 1; for(auto&& x : t) { if(first) first = 0; else o(' '); o(x); } }
    template<class T, size_t... idx> void otuple(const T& t, index_sequence<idx...>){ wtN(get<idx>(t)...); }
    template<class T> auto o(T& t, P<0>) -> VOID(tuple_size<T>{}){ otuple(t, make_index_sequence<tuple_size<T>::value>{}); }
    #undef VOID
}
template<class... Ts> void rd(Ts&... t){ (IO::i(t), ...); }
template<class T, class... Ts> void wtN(const T& t, const Ts&... ts){ IO::o(t); (IO::o((cout << ' ', ts)), ...); }
#undef unpack
constexpr ll debug_const(ll judge, ll debug) {
#ifdef DEBUG
    return debug;
#else
    return judge;
#endif
}
#ifdef DEBUG
ll __lg(ull x){ return 63 - __builtin_clzll(x); }
#define debug(...) { wtN(#__VA_ARGS__); wtN(":"); wt(__VA_ARGS__); }
#else
#define debug(...) void(0)
#endif
#define fst first
#define snd second
#define pb push_back
template<class T> using V = vector<T>;
template<class T, std::size_t N> using AR = array<T, N>;
#define MAIN
#include __FILE__
signed main() {int t = 1;if(__multi__) cin >> t;while(t --) XK::solve();}
#endif