#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <climits>
#include <cstring>

#define rep(i, m, n) for(int i=int(m);i<int(n);i++)
#define all(c) begin(c),end(c)

template<typename T1, typename T2>
inline void chmin(T1 &a, T2 b) { if (a > b) a = b; }

template<typename T1, typename T2>
inline void chmax(T1 &a, T2 b) { if (a < b) a = b; }

typedef long long int ll;
using ll = long long int;
using ull = long long unsigned int;
using Int = long long int;
using namespace std;
#define INF (1 << 30) - 1
#define INFl (ll)5e15
#define DEBUG 0
#define dump(x)  cerr << #x << " = " << (x) << endl
#define MOD 1000000007


//edit
class Solve {
public:
    Int N, M;
    double p;

    void init() {
        cin >> N >> M >> p;
    }

    void init(Int N_, Int M_, double p_) {
        N = N_;
        M = M_;
        p = p_;
    }


    double solve() {
        if (N == 1 && M == 1) {
            cout << p << endl;
            return p;
        }
        if (N > M) swap(N, M);
        if (N == 1) {
            double ans = (M - 2) * pow(p, 3) + 2 * pow(p, 2);
            cout << ans << endl;
            return ans;
        }

        Int cnt_corner = 4;
//        if (N == 1 && M == 1) cnt_corner = 1;
//        else if (N == 1 || M == 1) cnt_corner = 2;

        Int cnt_outer = max(0ll, N - 2) * 2 + max(0ll, M - 2) * 2;
        Int cnt_inner = N * M - cnt_corner - cnt_outer;

        double p_corner = pow(p, 3);
        double p_outer = pow(p, 4);
        double p_inner = pow(p, 5);

        double ans = cnt_corner * p_corner + cnt_outer * p_outer + cnt_inner * p_inner;
        cout << ans << endl;
        return ans;
    }
};

class Fool {
public:
    Int N, M;
    double p;

    void init() {
        cin >> N >> M >> p;
    }

    void init(Int N_, Int M_, double p_) {
        N = N_;
        M = M_;
        p = p_;
    }

    double solve() {
        // モンテカルロ法で解く
        Int mon = (Int) 1e3;
        Int total_score = 0;

        rep(_, 0, mon) {
            vector<vector<Int>> field(N + 2, vector<Int>(M + 2));
            for (int i = 1; i <= N; ++i) {
                for (int j = 1; j <= M; ++j) {
                    Int R = 1000000;
                    if (rand() % R < R * p) {
                        field[i][j] = 1;
                    } else {
                        field[i][j] = -1;
                    }
                }
            }
            Int score = 0;
            for (int i = 1; i <= N; ++i) {
                for (int j = 1; j <= M; ++j) {
                    bool flag = field[i][j] == 1;
                    int di[] = {1, 0, -1, 0};
                    int dj[] = {0, 1, 0, -1};
                    for (int k = 0; k < 4; ++k) {
                        if (field[i + di[k]][j + dj[k]] == -1) {
                            flag = false;
                        }
                    }
                    if (flag) score++;
                }
            }
            total_score += score;
        }

        double ans = 1. * total_score / mon;
        cout << ans << endl;

        return ans;
    }


};

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);

//    Solve().solve();
    bool debug = true;
    debug = false;

    if (!debug) {
        Solve solve;
        solve.init();
        solve.solve();
    } else {
        while (true) {
            Int MIN_N = 1;
            Int MAX_N = 100;
            Int MIN_M = 1;
            Int MAX_M = 100;
            Int R = 10000000;
            Int N = MIN_N + rand() % (MAX_N - MIN_N + 1);
            Int M = MIN_M + rand() % (MAX_M - MIN_M + 1);
            double p = 1. * (rand() % R) / R;

            cout << "Input" << endl;
            cout << N << " " << M << " " << p << endl;

            cout << "Output" << endl;
            Solve solve;
            solve.init(N, M, p);
            double sans = solve.solve();

            Fool fool;
            fool.init(N, M, p);
            double fans = fool.solve();

            double sotai = (sans - fans) / fans;
            if (fabs(sotai) > 1e-1 && abs(sans - fans) > 1e-1) {
                exit(-1);
            }
        }
    }


    return 0;
}