#include <fstream>
using namespace std;
int n, m, x, i, j, i1, j1, maxim;
short s[301][301];
bool a[301][301];
int main()
{
    ifstream fin ("teren.in");
    ofstream fout ("teren.out");
    fin>>n>>m>>x;
    maxim=0;
    for (i=1; i<=n; i++)
        for (j=1; j<=m; j++)
            fin>>a[i][j];
    for (i=1; i<=n; i++)
        for (j=1; j<=m; j++)
            s[i][j]=s[i-1][j]+s[i][j-1]-s[i-1][j-1]+a[i][j];
    for (i=1; i<=n; i++)
        for (j=1; j<=m; j++)
            for (i1=i; i1<=n; i1++)
                for (j1=j; j1<=m; j1++)
                    if (s[i1][j1]-s[i-1][j1]-s[i1][j-1]+s[i-1][j-1] <=x && (i1-i+1)*(j1-j+1)>maxim)
                        maxim=(i1-i+1)*(j1-j+1);
    fout<<maxim;

}