while (<DATA>) {
  my @tok;
  while (s/^([A-Z][a-z]?|[0-9])//) {
    push @tok, $1;
  }
  print join('-', @tok), "\n";
}

__DATA__
TTh7
MF4
ThF1

Results
T-Th-7
M-F-4
Th-F-1