var a: array [1..100, 1..100] of integer;
n,i,l,k: integer;
begin
k:=0;
read(n);
for i:= 1 to n do
begin
for l:= 1 to n do
begin
read (a[i,l]);
if a[i,l]=1 then  k:=k+1;
end;
end;
write(k);
end.