1) var n,a,kol,sum,i:int64;
begin
read(n);
for i:=1 to n do begin
read(a);
if (i mod 2)=1 then begin
inc(sum,a);
inc(kol);
end;
end;
writeln(sum/kol);
end.
2)var n,a,kol,sum,i,pr:int64;
begin
read(n);
for i:=1 to n do begin
read(a);
if (i mod 2)=0 then begin
inc(sum,a);
end;
if a<0 then pr:=pr*a;<br> if (a mod 2)=1 then inc(kol);
end;
writeln(sum,' ',pr,' ',kol);
end.
3) var ma,n,a,i:int64;
begin
read(n);
for i:=1 to n do begin
read(a);
if (a>ma) then begin
ma:=a;
end;
end;
writeln(ma);
end.