import sys

c=[list(map(float,s[:-1].split(","))) for s in sys.stdin]

x0,y0=c[0]

x1,y1=c[1][0]-x0,c[1][1]-y0

s=0

for ex,ey in c[2:]:

    x2,y2=ex-x0,ey-y0

    s+=abs(x1*y2-x2*y1)

    x1,y1=x2,y2

print(s/2)
import sys

x0,y0=list(map(float,input()[:-1].split(",")))

x1,y1=list(map(float,input()[:-1].split(",")))

x1,y1=x1-x0,y1-y0

s=0

for e in sys.stdin:

    ex,ey=list(map(float,e[:-1].split(",")))

    x2,y2=ex-x0,ey-y0

    s+=abs(x1*y2-x2*y1)

    x1,y1=x2,y2

print(s/2)
import sys

c = [list(map(float, s[:-1].split(","))) for s in sys.stdin]
x0, y0 = c[0]
x1, y1 = c[1][0] - x0, c[1][1] - y0
s = 0
for ex, ey in c[2:]:
    x2, y2 = ex - x0, ey - y0
    s += abs(x1 * y2 - x2 * y1)
    x1, y1 = x2, y2
print(s / 2)

import sys

x0, y0 = list(map(float, input()[:-1].split(",")))
x1, y1 = list(map(float, input()[:-1].split(",")))
x1, y1 = x1 - x0, y1 - y0
s = 0
for e in sys.stdin:
    ex, ey = list(map(float, e[:-1].split(",")))
    x2, y2 = ex - x0, ey - y0
    s += abs(x1 * y2 - x2 * y1)
    x1, y1 = x2, y2
print(s / 2)

-c = [list(map(float, s[:-1].split(","))) for s in sys.stdin] -x0, y0 = c[0] -x1, y1 = c[1][0] - x0, c[1][1] - y0 +x0, y0 = list(map(float, input()[:-1].split(","))) +x1, y1 = list(map(float, input()[:-1].split(","))) +x1, y1 = x1 - x0, y1 - y0 -for ex, ey in c[2:]: +for e in sys.stdin: +    ex, ey = list(map(float, e[:-1].split(",")))