x1,y1,x2,y2,x3,y3 = eval(input("삼각형의 세 꼭짓점을 입력하세요: "))
s1 = ((x1-x2)**2+(y1-y2)**2)**0.5
s2 = ((x1-x3)**2+(y1-y3)**2)**0.5
s3 = ((x3-x2)**2+(y3-y2)**2)**0.5

s= (s1+s2+s3)/2

area = (s*(s-s1)*(s-s2)*(s-s3))**0.5

print("삼각형의 넓이는 ",area,"입니다.")
