int main(){
int Row=100,Col=100;
int sz[Row][Col];
int n;
int row1;int row2;int i;
int col1;int col2;int k;
scanf("%d",&n);
for(i=0;i<n;i++){
for(k=0;k<n;k++){
scanf("%d",&sz[i][k]);}}
int judge=0;
for(i=0;judge==0&&i<n;i++){
for(k=0;judge==0&&k<n;k++){
if(sz[i][k]==0){
judge=1;

row1=i;

col1=k;}}}
for(i=n-1;judge==1&&i>0;i--){
for(k=n-1;judge==1&&k>0;k--){
if(sz[i][k]==0){

row2=i;

col2=k;
judge=0;}}}
int s;
s=(row2-row1-1)*(col2-col1-1);
printf("%d",s);
return 0;
}