from sys import stdin
input = stdin.readline

N = int(input())
AB = [list(map(int, input().split())) for _ in range(N)]

sumA, sumB = 0, 0
for A, B in AB:
    sumA += A
    sumB += B

ans = 0
for A, B in AB:
    sumA -= A
    sumB -= B
    ans += max(A*sumB, B*sumA)

print(ans)