string.LastIndexOf()

Question

Hi guys. I don't know if it is only me,or what,but simple function from class String - LastIndexOf() works for me well only if there is only first attribute assigned and nothing else. If I try write something like this : string strS = "abcdefghijkl"; int a = strS.LastIndexOf("c",0,5); it always throw exception : Count must be positive and count must refer to a location within the string/array/collection. Does it happend to You too or is just something wrong with me ? Thanks. Rodenpro