"use strict";
function Main(input) {
    let cin = new Inputer(input);
    let N = cin.getInt(), A = cin.getIntArray(N);
    let B = new Array(N);
    let fu = 0, min = 1e10;
    for (let n = 0; n < N; n++) { 
        if (A[n] < 0) B[n] = -A[n], fu++;
        else B[n] = A[n];
        if (min > B[n]) min = B[n];
    }
    let ans = B.reduce((ac, v) => ac + v, 0);
    if (fu % 2 != 0) ans -= min * 2;
    console.log(ans);
}
class Inputer{constructor(t){if(typeof t=='undefined')throw new Error('引数（stdin）を省略できません！');this.cnt=0,this.items=t.split(/\n|\s/)}getInt(){return this.items[this.cnt++]-0}getIntArray(t){if(typeof t=='undefined')throw new Error('引数（1以上）を省略できません！');let r=new Array(t);for(let e=0;e<t;e++)r[e]=this.getInt();return r}getStr(){return this.items[this.cnt++]}getStrArray(t){if(typeof t=='undefined')throw new Error('引数（1以上）を省略できません！');let r=new Array(t);for(let e=0;e<t;e++)r[e]=this.getStr();return r}}
if (typeof window == "undefined") Main(require("fs").readFileSync("/dev/stdin", "utf8"));