function Main(input) {
  var n = input.split("\n")[0];
  var a = input.split("\n")[1].split(" ");
  var sum = 0;
  var min = Infinity;
  var minusCount = 0;
  for(var i of a){
  	sum += Math.abs(i);
    if(i<0)minusCount++;
    if(Math.abs(i)<min)min = Math.abs(i);
  }
  if(minusCount%2==1)sum -= min*2;
  console.log(sum);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));