"use strict";
    
const main = arg => {
    arg = arg.trim().split("\n");
    const N = ~~arg[0];
    const b = arg[1].split(" ").map(n=>~~n);
    
    const minusCnt = b.filter(n=>n<0).length;
    
    if(minusCnt % 2 === 0) {
        console.log("a")
        console.log(b.map(n=>Math.abs(n)).reduce((m,n)=>m+n));
    } else {
        console.log(b.map(n=>Math.abs(n)).reduce((m,n)=>m+n) - (b.map(n=>Math.abs(n)).sort((a,b)=>a-b)[0] * 2));
    }
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));