'use strict'

//定数
const INF  =  900719925474099 // Math.floor(Number.MAX_SAFE_INTEGER / 10);


function Main(input){
	let temp = input.trim().split('\n');
	let n = parseInt(temp[0]);
	let a = temp[1].split(' ').map((v)=>parseInt(v));

	let min = INF;
	let sum = 0;
	let count = 0;
	let v;
	for(let i=0;i<n;i++){
		if(a[i]<0){
			count++;
		}
		v = Math.abs(a[i]);
		min = Math.min(min,v);
		sum += v;
	}
	if( (count%2) === 1 ){
		sum -= min*2;
	}
	//回答出力
	console.log(sum);
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));
