var a:array [1..100] of integer;
i,n,s:integer;
Begin
randomize;
n:=12;
for i:= 1 to n do begin
a[i]:=random(n*10)- 10*n div 2 ;
write(a[i]:4);
if i mod 10=0 then writeln;
end;
for i:= 1 to n do begin
if i mod 2 =0 then
s:=s+a[i];
end;
writeln(s);
End.