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();
    
    let alpha = 'abcdefghijklmnopqrstuvwxyz'.split('');
    
    let maxHeight = -1;
    word.split('').forEach(char => {
        let height = h[alpha.indexOf(char)];
        
        if (height > maxHeight) {
            maxHeight = height;
        }
    });
    
    console.log(maxHeight * word.length);
}