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 s(a) {
	let b = [];
	for (var k=0, len_a=a.length; k<len_a; k++) {
		for (var i=0; i<len_a-k; i++) {
			b.push(a.slice(i, i+k+1).reduce((c, d) => Math.max(c, d), 0));
		}
	}
	return b;
}

function solve(A) {
    let mma = s(s(A));
    return mma.reduce((c, d) => c + d, 0);
}

function main() {
    var n = parseInt(readLine());
    a = readLine().split(' ');
    a = a.map(Number);
    var result = solve(a);
    process.stdout.write("" + result + "\n");

}