/*
TASK:socks
LANG:C++
*/
#include <iostream>
#include <iomanip.h>
using namespace std;
int main()
{
int a, b;
int m1[32];
int m2[32];
cin >> a >> b;
for (int i = 1; i<=a; i++)
cin >> m1[i];
for (int j = 1; j<=a+1; j++)
cin >> m2[j];
cout << a*b << ".00" << "\n";
return 0;
}
