process.stdin.resume();
process.stdin.setEncoding('ascii');

var input_stdin = "";
var input_stdin_array = "";
var input_currentline = 0;

process.stdin.on('data', function (data) {
    input_stdin += data;
});

process.stdin.on('end', function () {
    input_stdin_array = input_stdin.split("\n");
    main();    
});

function readLine() {
    return input_stdin_array[input_currentline++];
}

/////////////// ignore above this line ////////////////////

function main() {
    h = readLine().split(' ');
    h = h.map(Number);
    var word = readLine().split("");
    
    var maxH = 0;
    word.forEach((w) => {
        var char = w.charCodeAt(0) - 97;
        maxH = Math.max(h[char],maxH);
    });
    console.log(maxH * word.length);
    

}