import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int m = sc.nextInt();
        double p = sc.nextDouble();
        double ans;
        if (n == 1 && m == 1) {
            ans = p;
        } else if (n == 1) {
            ans = Math.pow(p, 2) * 2 + Math.pow(p, 3) * (m - 2);
        } else if (m == 1) {
            ans = Math.pow(p, 2) * 2 + Math.pow(p, 3) * (n - 2);
        } else {
            ans = Math.pow(p, 3) * 4 + Math.pow(p, 4) * (m - 2 + n - 2) * 2 + Math.pow(p, 5) * ((long)n * m - n * 2 - m * 2 + 4);
        }
        System.out.println(ans);
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}