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; 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.