var
n,max,q,i:integer;
m:array[1..100] of integer;
begin
readln(n); // ÷èñëî ÿ÷ååê â ìàññèâå 1<=n<=100
for i:=1 to n do
readln(m[i]);
for i:=1 to n do
begin
if m[i]=0 then inc(q);
if q>max then max:=q;
if m[i]<>0 then q:=0;
end;
writeln(max);
end.