#include #define LLI long long int #define FOR(v, a, b) for(LLI v = (a); v < (b); ++v) #define FORE(v, a, b) for(LLI v = (a); v <= (b); ++v) #define REP(v, n) FOR(v, 0, n) #define REPE(v, n) FORE(v, 0, n) #define REV(v, a, b) for(LLI v = (a); v >= (b); --v) #define ALL(x) (x).begin(), (x).end() #define RALL(x) (x).rbegin(), (x).rend() #define ITR(it, c) for(auto it = (c).begin(); it != (c).end(); ++it) #define RITR(it, c) for(auto it = (c).rbegin(); it != (c).rend(); ++it) #define EXIST(c,x) ((c).find(x) != (c).end()) #define fst first #define snd second #define popcount __builtin_popcount #define UNIQ(v) (v).erase(unique(ALL(v)), (v).end()) #define bit(i) (1LL<<(i)) #ifdef DEBUG #include #else #define dump(...) ((void)0) #endif #define gcd __gcd using namespace std; template constexpr T lcm(T m, T n){return m/gcd(m,n)*n;} template void join(ostream &ost, I s, I t, string d=" "){for(auto i=s; i!=t; ++i){if(i!=s)ost< istream& operator>>(istream &is, vector &v){for(auto &a : v) is >> a; return is;} template bool chmin(T &a, const U &b){return (a>b ? a=b, true : false);} template bool chmax(T &a, const U &b){return (a void fill_array(T (&a)[N], const U &v){fill((U*)a, (U*)(a+N), v);} struct Init{ Init(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(12); cerr << fixed << setprecision(12); } }init; int main(){ LLI N, M; double P; while(cin >> N >> M >> P){ double ans = 0; LLI c0 = 0, c1 = 0, c2 = 0, c3 = 0, c4 = 0; if(N == 1 and M == 1){ c0 = 1; }else{ if(N == 1){ c1 = 2; c2 = M-c1; }else if(M == 1){ c1 = 2; c2 = N-c1; }else{ c2 = 4; c3 = (N-2) * 2 + (M-2) * 2; c4 = N * M - c3 - c2; } } ans += P * pow(P, 0) * c0; ans += P * pow(P, 1) * c1; ans += P * pow(P, 2) * c2; ans += P * pow(P, 3) * c3; ans += P * pow(P, 4) * c4; cout << ans << endl; } return 0; }