#include<iostream>
using namespace std;
unsigned long int da(unsigned long int x,unsigned long int y)
{
if (x >y)
{return x;}
else
{return y;}
}
main()
{
unsigned long int k,h,he=0;
cin >>h;
cin >> k;
for (unsigned long int q=1;q<=h;q++)
{unsigned long int x[k-1];
for (unsigned long int i=0;i<=k-1;i++)
{
cin >> x;
}
unsigned long int y[100][100];
for(unsigned long int i=0;i<=k-1;i++)
{
y=x*2;
}
for (unsigned long int j=1;j<=k-1;j++)
{
for (unsigned long int i=0;i<=k-1-j;i++)
{
y[i+j]= da(2*y[i+j-1]+2*x[i+j],2*y[i+1][i+j]+2*x);
}
}
he+=y[0][k-1];
}
cout <<he;
system("pause");
}
