#include <cstdio>
using namespace std;

FILE *f=fopen ("teren.in","r");
FILE *g=fopen ("teren.out","w");

bool v[305][305];
int ind[305][305],s[305][305];

int main(){
	int n,m,x,max=-1;
	
	fscanf (f,"%d%d%d",&n,&m,&x);
	
	for (int i=1;i<=n;++i){
		for (int j=1;j<=m;++j){
			fscanf (f,"%d",&v[i][j]);
			s[i][j]=v[i][j]+s[i-1][j]+s[i][j-1]-s[i-1][j-1];
		}
	}
	
	for (int i=1;i<=n;++i){
		for (int j=1;j<=m;++j){
			if (s[i][j]<=x && i*j>max) max=i*j;
		}
	}
	
	fprintf (g,"%d",max);
	
	
	return 0;
}