ЦЧД. Сума трьохзначних чисел Free_Pascal IDE

program Free_Pascal ;

uses CRT;
Var a,b,c,f,E:integer;
BEGIN
Writeln('Vvesty tryznashne shislo');
Read(c);
a:= c mod 10;
b:= c div 100;
f:= c div 10 mod 10;
E:= a+b+f;
writeln(E);
Readln;
Readln;

END.