#include <iostream>
#include <iomanip>  
using namespace std;

int main() 
{
	int m, n;
	cin >> m >> n;
	double a[m*n];
	double sum1 = 1, sum2 = 1, sum3 = 1;
	double sum = 0;
	for (int i = 1; i <= m*n; i++)
	{
		cin >> a[i];
		if (i <= m)
		{
			sum1 *= a[i];
		}
		if ((i > m) && (i <= 2*m))
		{
			sum2 *= a[i];
		}
		if ((i > (n - 1)*m) && (i <= n*m))
		{
			sum3 *= a[i];
		}
	}
	cout << setprecision(15) << sum1 + sum2 + sum3; 
	return 0;
}