def fs(L, l1, r1):
    if l1 >= r1:
        return
    l, r = l1, r1
    P = L[(l1 + r1) // 2]
    while l <= r:
        while abs(L[l]) < abs(P):
            l += 1
        while abs(L[r]) > abs(P):
            r -= 1
        if l <= r:
            L[l], L[r] = L[r], L[l]
            l += 1
            r -= 1
    fs(L, l1, r)
    fs(L, l, r1)


def main():
    N = int(input())
    L = [int(i) for i in input().split()]
    fs(L,0, len(L) - 1)
    l = 0
    r = len(L) - 1
    while l < r:
        if L[r] < 0:
            if L[l] < 0:
                l += 1
            else:
                L[r] = -L[r]
                L[l] = -L[l]
                l += 1
                r -= 1
        else:
            r -= 1
    print(sum(L))