function Main(input){
    input = input.split("\n");
    var arr = input[1].split(" ").map(Number).sort(function(a,b){return a-b;});
    //console.log(arr)
    //console.log(arr)
    for(var i=0;i<Math.floor(arr.length/2)*2;i+=2){
      //  if(!arr[i+1]) break;
    //    console.log([i,arr[i],arr[i+1]])
        if(arr[i]<=0&&arr[i+1]<=0){
            arr[i]*=-1;
            arr[i+1]*=-1;
        }else if(arr[i]<0){
            if(arr[i]*-1>arr[i+1]){
                arr[i]*=-1;
                arr[i+1]*=-1;
            }
        }
    }
  //  console.log(arr)
    var sum = 0n;
    arr.forEach(function(val){
    //    console.log(val)
        sum += BigInt(val);
    });
    console.log(sum.toString())
}Main(require("fs").readFileSync("/dev/stdin", "utf8").trim());
