function nod(a, b: LongInt): LongInt;
  begin
   if b = 0 then 
    nod := a
   else
    nod := nod (b, a mod b)
end;

function nodN(a : array of LongInt): LongInt;
var 
  tmpGCD,i,n : LongInt;
begin
  n:= Length(a);
  i:=0;
  TmpGCD := nod(a[i],a[i+1]);
  
  while ((i+1<n-1) and (tmpGCD<>1)) do
  begin
     i:=i+1;
     tmpGCD := nod(a[i],tmpGCD);
  end; 
  nodN := tmpGCD;
end;

var 
  a:array of LongInt;
  n,i: LongInt;
begin
  write('Enter count of numbers: ');
  readln(n);
  SetLength(a,n);
  for i:=0 to n-1 do
  begin
    write('Enter a['+i+']: ');
    readln(a[i]);
  end; 
  writeln('GCD = '+nodN(a));
end.