function Main(input) {
    const N = parseInt(input.shift())
    const As = input.map(x => parseInt(x));

    var isOdd = false;
    var absSum = 0;
    var minAbs = Number.MAX_SAFE_INTEGER;

    As.forEach(element => {
        if (element < 0) {
            isOdd = !isOdd;
            element *= -1;
        }
        absSum += element;
        minAbs = Math.min(minAbs, element);
    });

    if (isOdd) {
        absSum -= minAbs * 2;
    }

    console.log(absSum);
}

// 1行入力の場合
// Main(require("fs").readFileSync("/dev/stdin", "utf8").trim());

// 改行で分割
// Main(require("fs").readFileSync("/dev/stdin", "utf8").trim().split(/\n/));

// 改行・空白で分割
Main(require("fs").readFileSync("/dev/stdin", "utf8").trim().split(/\n|\s/));