program eightqueens (output);
var i: integer;
   a: array [ 1.. 8] of boolean;
   b: array [ 2..16] of boolean;
   c: array [-7.. 7] of boolean;
   x: array [ 1.. 8] of integer;

procedure print;
   var k: integer;
begin for k := 1 to 8 do write(x[k]: 4);
   writeln
end {print} ;

procedure try(i: integer);
   var j: integer;
begin
   for j := 1 to 8 do
      if a[j] and b[i+j] and c[i-j] then
      begin x[i] := j;
         a[j] := false; b[i+j] := false; c[i-j] := false;
         if i < 8 then try(i+1) else print;
         a[j] := true; b[i+j] := true; c[i-j] := true
      end
end {try} ;

begin
   for i :=  1 to  8 do a[i] := true;
   for i :=  2 to 16 do b[i] := true;
   for i := -7 to  7 do c[i] := true;
   try (1)
end .