"use strict";
function Main(input) {
    let cin = new Inputer(input);
    let N = cin.getInt();
    let A = cin.getIntArray(N);
    for (let n = 0; n < N-1; n++) {
        let p = A[n] + A[n+1];
        let q = 0 - A[n] - A[n+1];
        if (p < q) A[n] *= -1, A[n+1] *= -1;
    }
    console.log(A.reduce((ac, v) => ac + v, 0));
}
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"));