const
 n=7;
var
 a:array[1..3*n] of real;
 b:array[1..n] of real;
 i:integer;
begin
 for i:=1 to 3*n do
  begin
   write ('a[',i:2,']= ');
   readln (a[i]);
  end;
 writeln;
 for i:=1 to 3*n do
  write(a[i]:8:3);
 writeln;
 writeln;
 for i:=1 to n do
  b[i]:=(a[1+(i-1)*3]+a[2+(i-1)*3]+a[3+(i-1)*3])/3;
 for i:=1 to n do
  write(b[i]:8:3);
 readln
end.