import sys
readline = sys.stdin.readline

N = int(readline())
A, B = [0] * N, [0] * N
for i in range(N):
    A[i], B[i] = map(int, readline().split())
    
SA, SB = sum(A), sum(B)
ans = 0
for i in range(N):
    ans += max(A[i] * (SB - B[i]), B[i] * (SA - A[i]) )
    SA -= A[i]
    SB -= B[i]

print(ans)