sub mu {
for(@s=($_[0],$c=0);$c<$_[2];){($_=shift@s or$c++,$s[@s]=0,next
)eq$_[1]&&return$c;$s[@s]="$_$1"if/^M/;/I$/and$s[@s]=$_.U;$s[
@s]="$`$'"while/UU/g;$s[@s]=$`.U.substr$',2while/I(?=II)/g}0
}