Polygon area

n = int(input())
vertices = []
for _ in range(n):
    x, y = map(int, input().split())
    vertices.append((x, y))

area_sum = 0
for i in range(n):
    x1, y1 = vertices[i]
    x2, y2 = vertices[(i + 1) % n]
    area_sum += x1 * y2 - x2 * y1

print(abs(area_sum))

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED