Programa para cual de los 3 numeros es mayor

program mayor;
uses wincrt;

var
a,c,b:integer;
begin
writeln('Coloque a');
readln(a);
writeln('Coloque b');
readln(b);
writeln('Coloque c');
readln(c);
if (a>b) and (a>C) then
write('mayor es A')
else
if (b>a) and (b>c) then
write('el mayor es B')
else
write ('el mayor es C');
end.