Error: 
Use of uninitialized value $pos in hash element at ./second_str_map.pl line 29, <B> line 298.
Use of uninitialized value $_ in split at ./second_str_map.pl line 28, <B> line 299.
Use of uninitialized value $pos in hash element at ./second_str_map.pl line 29, <B> line 299.
Use of uninitialized value $_ in split at ./second_str_map.pl line 28, <B> line 300.
Use of uninitialized value $pos in hash element at ./second_str_map.pl line 29, <B> line 300.
Use of uninitialized value $_ in split at ./second_str_map.pl line 28, <B> line 301.
Use of uninitialized value $pos in hash element at ./second_str_map.pl line 29, <B> line 301.