program bai_5;
uses crt;
var a,b,c :real;
BEGIN
write('nhap vao so a'); Readln(a);
write('nhap vao so b'); Readln(b);
write('nhap vao so c'); Readln(c);
if a<0 then a:=-a;
max:=a;
if max <b then max:=b;
if max<c then max:=c;
write('gia tri tuyet doi cua a la:',a);
write('so lon nhat trong ba so a,b,c la:',max);
Readln
END.
Thanks