#! /usr/bin/perl

@w = ('h','a','!');

@S = ('s1','s2');

%a = (
	  s0 => {s1 => 1.0},
	  s1 => {s1 => 0.6,
			 s2 => 0.2,
			 se => 0.2},
	  s2 => {s1 => 0.4,
			 s2 => 0.4,
			 se => 0.2}
	 )
;
%b = (
	  s1 => {h => 0.6,
			 a => 0.1,
			 '!' => 0.3},
	  s2 => {h => 0.1,
			 a => 0.7,
			 '!' => 0.2}
)
;


foreach $s (@S) {
  ${$alpha[0]}{$s} = ${$a{s0}}{$s} * ${$b{$s}}{$w[0]};
}


for ($i=0;$i < $#w ;$i++){
  foreach $s (@S) {
	foreach $sbar (@S) {
	  ${$alpha[$i+1]}{$s} += ${$alpha[$i]}{$sbar} * ${$a{$sbar}}{$s};
	}
	${$alpha[$i+1]}{$s} *= ${$b{$s}}{$w[$i+1]};
  }
}

foreach $s (@S) {
  $p += ${$alpha[$#w]}{$s}*${$a{$s}}{'se'};
}

print "$p\n";