Polygon area

def area(point1, point2, point3):
    (x1, y1) = point1
    (x2, y2) = point2
    (x3, y3) = point3

    return abs(x3 * (y1 - y2) + x1 * (y2 - y3) + x2 * (y3 - y1))


if __name__ == "__main__":
    n = int(input())
    points = []
    for i in range(n):
        point = list(map(int, input().split()))
        points.append(point)
    start = points[0]
    polygon = points[1:]
    total_area = 0
    for i in range(1, len(polygon)):
        total_area += area(start, polygon[i-1], polygon[i])
    print(total_area)

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: ACCEPTED