Написать программу, определяющую возможность перемещения белой шашки

Function FromAtoB(ax:char;ay:byte;bx:char;by:byte):Boolean;
Begin
  If (ax in ['a'..'h']) and (ay in [1..8]) then
    If (ax=bx) and (ay=by) then FromAtoB:=True
    else
    Begin
      FromAtoB:=FromAtoB(pred(ax),ay+1,bx,by) or FromAtoB(succ(ax),ay+1,bx,by);
    end
  else FromAtoB:=False;
end;
 
function pologenie(ax:char;ay:byte):boolean;
begin
    pologenie:=not odd(ord(ax)+ay)
end;
 
const a:array[boolean] of string[3]=('NO','YES');
var ax,bx:char;
    ay,by:byte;
    s:string[5];
    code:integer;
begin
  assign(input,'input.txt');reset(input);
  assign(output,'output.txt');rewrite(output);
  readln(s);
  ax:=s[1];val(s[2],ay,code);
  bx:=s[4];val(s[5],by,code);
  if pologenie(ax,ay)
    then writeln(a[FromAtoB(ax,ay,bx,by)])
    else writeln(a[pologenie(ax,ay)])
end.

var
f1,f2:text;
a:string;
begin
assign(f1,'input3.txt');
reset(f1);
assign(f2,'output3.txt');
rewrite(f2);
readln(f1,a);
if (abs(ord(a[4])-ord(a[1]))=1)and(ord(a[5])-ord(a[2])=1)then writeln(f2,'YES') else writeln(f2,'No');
close(f1);
close(f2);
end.

const NoYes: array [Boolean] of String[3] = ('NO','YES');
var a: String;
begin
  Assign(input,'input3.txt'); Reset(input);
  Assign(output,'output3.txt'); Reset(output);
  ReadLn(a);
  WriteLn(NoYes[(abs(ord(a[4])-ord(a[1]))=1) and (ord(a[5])-ord(a[2])=1)]);
end.

const NoYes: array [Boolean] of String[3] = ('NO','YES');
var a: String;
begin
  Assign(input,'input3.txt'); Reset(input);
  Assign(output,'output3.txt'); Reset(output);
  ReadLn(a); WriteLn(NoYes[
    (a[1] in ['a'..'h']) and (a[2] in ['1'..'8']) and
    Odd(Ord(a[1])-Ord('a')+Ord(a[2])-Ord('0')) and
    (Abs(Ord(a[4])-Ord(a[1]))=1) and (Ord(a[5])-Ord(a[2])=1)]);
end.

const NoYes: array [Boolean] of String[3] = ('NO','YES');
var a: String;
begin
  Assign(input,'input3.txt'); Reset(input);
  Assign(output,'output3.txt'); Reset(output);
  ReadLn(a); WriteLn(NoYes[
    (a[1] in ['a'..'h']) and (a[2] in ['1'..'8']) and
    (a[4] in ['a'..'h']) and (a[5] in ['1'..'8']) and
    Odd(Ord(a[1])-Ord('a')+Ord(a[2])-Ord('0')) and
    (Abs(Ord(a[4])-Ord(a[1]))<=Ord(a[5])-Ord(a[2]))]);
end.

var
f1,f2:text;
a:string;
begin
assign(f1,'input3.txt');
reset(f1);
assign(f2,'output3.txt');
rewrite(f2);
readln(f1,a);
if abs(ord(a[4])-ord(a[1]))=ord(a[5])-ord(a[2])then writeln(f2,'YES') else writeln(f2,'No');
close(f1);
close(f2);
end.