uses crt;var ch,a:integer;
begina:=0;for i:=1 to 30 dobeginreadln(ch);a:=a*ch;end;writeln(a);readln;
end.
uses crt;
var ch,a:integer;
begin
a:=0;
for i:=1 to 30 do
begin
readln(ch);
a:=a*ch;
end;
writeln(a);
readln;
end.