I,R=input,range
N=int(I())
A=[0]*N
B=[0]*N
a=b=c=0
for i in R(N):
	A[i],B[i]=map(int,I().split())
	a+=A[i]
	b+=B[i]
for i in R(N):
	a-=A[i]
	b-=B[i]
	c+=max(A[i]*b,a*B[i])
print(c)