It`s my Pascal code:
type mass=array[1..101] of shortint;
var i,j,j1:integer; s:string[101]; m1:mass;
begin
read(s); j1:=length(s);
for i:=1 to j1 do
begin
m1[i]:=ord(s[i])-97;
end; j:=5;
for i:=1 to j1 do
begin
if m1[i]>=j-1 then begin m1[i]:=m1[i]-j; j:=m1[i]+j; end
else begin m1[i]:=m1[i]+26-j; j:=m1[i]-26+j end
end;
for i:=1 to j1 do write(chr(m1[i]+97)); end.

Give me some tests were my program will give wrong answer..