<>;$_=<>;y/a-g/h/;y/l-s/t/;y/vw/x/;++$-while((((s/h//||s/i//)&&s/i//||s/j//||s/k//)&&s/k//||s/t//||s/u//)&&s/u//||s/x//||s/y//)&&s/y//||s/z//;print$-