let N = Int(readLine()!)!
let A = readLine()!.characters.split(" ").map{Int(String($0))!}
if A.reduce(0)({$0+($1<0 ?1:0)}) % 2 == 0 {
    print(A.reduce(0){$0+abs($1)})
} else {
    print(A.reduce(0){$0+abs($1)}-A.map{abs($0)}.minElement()!*2)
}