#bai 6 -copy code from internet =)) s = "this is a string, let's find out the most common and least common charater" max_letter = s[0] min_letter = s[0] max = s.count(s[0]) min = s.count(s[0]) for c in s: if c is not " ": if s.count(c) > max: max_letter = c max = s.count(c) if s.count(c) < min: min_letter = c min = s.count(c) print ("chu cai xuat hien nhieu nhat la %s , voi %s lan" %(max_letter, max)) print ("chu cai xuat hien it nhat la %s , voi %s lan" %(min_letter, min))