#include <fstream>

using namespace std;

ifstream fin ("teren.in");
ofstream fout("teren.out");

int teren[301][301], arie, n, m, x, maxim, suma;
bool tipTeren;

int main()
{
    fin >> n >> m >> x;
    for(int i = 1; i <= n; i++)
    {
        for(int j = 1; j <= m; j++)
        {
            fin >> tipTeren;
            teren[i][j] = teren[i - 1][j] + tipTeren;
        }
    }
    for(int i1 = 1; i1 <= n; i1++)
    {
        for(int i2 = i1; i2 <= n; i2++)
        {
            int st = 1;
            int dr = 1;
            suma = 0;
            while(dr <= m)
            {
                suma += teren[i2][dr] - teren[i1 - 1][dr];
                while(suma > x)
                {
                    suma -= teren[i2][st] - teren[i1 - 1][st];
                    st++;
                }
                arie = (i2 - i1 + 1) * (dr - st + 1);
                if(maxim < arie)
                {
                    maxim = arie;
                }
                dr++;
            }
        }
    }
    fout<<maxim;
}