$ perl -0777 -nE '
    my $count = 0;
    $count += length $2 while /(.)(\1+)/g;
    say $count;
' <<< "1112223333"
7

$ perldoc perlop | perl -0777 -nE '
    my $count = 0;
    $count += length $2 while /(.)(\1+)/g;
    say $count;
'
22788