uses crt;
var s:array[1..80]of char;
i,n,k:integer;
begin
write('N -> ');
readln(N);
write('Введите символы -> ');
for i:=1 to N do read(s[i]);
readln;
k:=0;
for i:=1 to N div 2 do if s[i]<>s[N-i+1] then inc(k);
writeln(k);
readln;
end.
uses crt;
var s:array[1..80]of char;
i,n,k:integer;
begin
write('N -> ');
readln(N);
write('Введите символы -> ');
for i:=1 to N do read(s[i]);
readln;
k:=0;
for i:=1 to N div 2 do if s[i]<>s[N-i+1] then inc(k);
writeln(k);
readln;
end.