A.py

ver = []
def area(A, B, C):
    return 0.5 * abs((ver[B][0] - ver[A][0])*(ver[C][1] - ver[A][1]) - (ver[C][0] - ver[A][0])*(ver[B][1] - ver[A][1]))
n = int(input())
for i in range(n):
    x, y = map(int, input().split())
    ver.append([x, y])
A = 0; B = 1; C = 2
bA= A; bB= B; bC= C
while True:
    while True:
        while area(A, B, C) <= area(A, B, (C+1)%n):
          C = (C+1)%n
        if area(A, B, C) <= area(A, (B+1)%n, C):
            B = (B+1)%n
            continue
        else:
            break
    if area(A, B, C) > area(bA, bB, bC):
        bA = A
        bB = B
        bC = C

    A = (A+1)%n
    if A==B:
        B = (B+1)%n
    if B==C: C = (C+1)%n
    if A==0: break

ans = area(bA, bB, bC)
print('{0:.1f}'.format(ans))