n = int(input())
A = list(map(int, input().split()))
AIDX = []
for i in range(2 * n):
    AIDX.append((A[i], i))

AIDX.sort(key=lambda x: x[0], reverse=True)
for i in range(0, 2 * n, 2):
    curr_ind = AIDX[i][1]
    next_ind = AIDX[i + 1][1]
    if curr_ind // 2 == next_ind // 2:
        continue
    if curr_ind % 2 == 0:
        curr_ind_pair = curr_ind + 1
    else:
        curr_ind_pair = curr_ind - 1
    A[next_ind], A[curr_ind_pair] = A[curr_ind_pair], A[next_ind]
    break

ans = 0
for i in range(0, 2 * n, 2):
    ans += A[i] * A[i + 1]
print(ans)