Проверка признака делимости числа на 11

var
a:integer;
f:boolean;
begin
writeln('vvedit a');
readln(a);
f:=false;
if a mod 11=0 then
f:=true;
if f then writeln('delitsa')
else writeln('ne delitsa');
end.

var
a,s,s1:string;
f:boolean;
i,k,x,x1,x2:longint;
begin
writeln('vvedit a');
readln(a);
for i:=1 to length(a) do begin
if not odd(i) then
s:=s+a[i];
if odd(i) then
s1:=s1+a[i];
end;
val(s,x,k);
val(s1,x1,k);
x2:=abs(x1-x2);
if (x=x1) or (x2 mod 11=0) then writeln('delitsa')
else writeln('ne delitsa');
end.

var
a:string;
i,s1,s2,m,n:integer;
begin
readln(a);
for i:=1 to length(a) do
begin
val(a[i],n,m);
if i mod 2<>0 then s1:=s1+n else s2:=s2+n;
end;
if (s1=s2)or(abs(s1-s2) mod 11=0)then writeln('yes')else writeln('no');
readln;
end.

var
a,s,s1:string;
i,k,x,x1,x2,p,p1,p3,l:longint;
begin
writeln('vvedit a');
readln(a);
for i:=1 to length(a) do begin
if not odd(i) then
s:=s+a[i];
if odd(i) then
s1:=s1+a[i];
end;
val(s,x,k);
val(s1,x1,k);
p:=0;
while x<>0 do begin
l:=x mod 10;
p:=p+l;
x:=x div 10;
end;
p1:=0;
while x1<>0 do begin
l:=x1 mod  10;
p1:=p1+l;
x1:=x1 div 10;
end;
p3:=abs(p-p1);
if (p=p1) or (p3 mod 11=0) then writeln('delitsa')
else writeln('ne delitsa');
end.