Polygon area

n = int(input())
corners = []

def Area(corners, n):
    area = 0.0
    for i in range(n):
        j = (i + 1) % n
        area += corners[i][0] * corners[j][1]
        area -= corners[j][0] * corners[i][1]
    area = abs(area) / 2.0
    return area

for i in range(n):
    x, y = map(int, input().split())
    corners.append((x, y))

print(int(2 * Area(corners, n)))

Test 1

Verdict: ACCEPTED

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: ACCEPTED