Competitions

# WEEK5 GEOMETRY

# The area of a pyramid

A triangular pyramid is given the coordinates of its vertices **A**(`x`

; _{1}`y`

; _{1}`z`

), _{1}**B**(`x`

; _{2}`y`

; _{2}`z`

), _{2}**C**(`x`

; _{3}`y`

; _{3}`z`

), _{3}**S**(`x`

; _{4}`y`

; _{4}`z`

). Find the total surface area of the pyramid._{4}

#### Input

In four lines given the coordinates **x**, **y** and **z** of the pyramid vertices. All input data are integers, not exceeding **100** by absolute value.

#### Output

Print the total surface area of the pyramid, rounded to the nearest tenth.

Input example #1

-3 0 0 0 6 0 3 0 0 0 2 5

Output example #1

69.8