object Solution {

    def main(args: Array[String]) {
        val sc = new java.util.Scanner (System.in);
        var h = new Array[Int](26);
        for(h_i <- 0 to 25) {
           h(h_i) = sc.nextInt();
        }
        val word = sc.next();
        val longest = word.map( c => h(c.toByte - 97)).max
        println(longest * word.length)
    }
}