What is the problem with the length method?

Question

Java

Here is the code snippet:
String aff = args[0];
int b = aff.lenght() - 1;
When compiling, it gives the following error:
NON.java:4: error: cannot find symbol
int b = aff.lenght() - 1;
^
symbol: method length()
location: variable aff of type String
1 error
Thanks in advance!)