Buggy python submission (verdict: Runtime Error):
c=0
while True:
    n=input()
    if n==0:
        break
    c+=1
    a0, b0=map(int,raw_input().split())
    prev_a, prev_b=a, b
    tmp=0
    for i in range(n):
        a, b=map(int,raw_input().split())
        tmp+=(a-prev_a)**2+(b-prev_b)**2
        prev_a, prev_b=a, b
    tmp+=(prev_a-a0)**2+(prev_b-b0)**2
    print c, tmp**0.5
    
   

Fixed submission:
c=0
while True:
    n=input()
    if n==0:
        break
    c+=1
    x0, y0=map(int,raw_input().split())
    prev_x, prev_y=x0, y0
    tmp=0
    for i in range(n-1):
        x,y=map(int,raw_input().split())
        tmp+=prev_x*y - prev_y*x
        prev_x, prev_y=x, y
    tmp+=prev_x*y0 - prev_y*x0
    print c, 0.5*abs(tmp)
    skip=raw_input()

Buggy python submission (verdict: Runtime Error):
c=0
while True:
    n=input()
    if n==0:
        break
    c+=1
    a0, b0=map(int,raw_input().split())
    prev_a, prev_b=a0, b0
    tmp=0
    for i in range(n):
        a, b=map(int,raw_input().split())
        tmp+=(a-prev_a)**2+(b-prev_b)**2
        prev_a, prev_b=a, b
    tmp+=(prev_a-a0)**2+(prev_b-b0)**2
    print c, tmp**0.5
    
   

Fixed submission:
c=0
while True:
    n=input()
    if n==0:
        break
    c+=1
    x0, y0=map(int,raw_input().split())
    prev_x, prev_y=x0, y0
    tmp=0
    for i in range(n-1):
        x,y=map(int,raw_input().split())
        tmp+=prev_x*y - prev_y*x
        prev_x, prev_y=x, y
    tmp+=prev_x*y0 - prev_y*x0
    print c, 0.5*abs(tmp)
    skip=raw_input()

Buggy python submission (verdict: Runtime Error):
c=0
while True:
    n=input()
    if n==0:
        break
    c+=1
    x0, y0=map(int,raw_input().split())
    prev_x, prev_y=x0, y0
    tmp=0
    for i in range(n):
        x,y=map(int,raw_input().split())
        tmp+=prev_x*y - prev_y*x
        prev_x, prev_y=x, y
    tmp+=prev_x*y0 - prev_y*x0
    print c, 0.5*abs(tmp)
    
   

Fixed submission:
c=0
while True:
    n=input()
    if n==0:
        break
    c+=1
    x0, y0=map(int,raw_input().split())
    prev_x, prev_y=x0, y0
    tmp=0
    for i in range(n-1):
        x,y=map(int,raw_input().split())
        tmp+=prev_x*y - prev_y*x
        prev_x, prev_y=x, y
    tmp+=prev_x*y0 - prev_y*x0
    print c, 0.5*abs(tmp)
    skip=raw_input()

Buggy python submission (verdict: Runtime Error):
c=0
while True:
    n=input()
    if n==0:
        break
    c+=1
    x0, y0=map(int,raw_input().split())
    prev_x, prev_y=x0, y0
    tmp=0
    for i in range(n-1):
        x,y=map(int,raw_input().split())
        tmp+=prev_x*y - prev_y*x
        prev_x, prev_y=x, y
    tmp+=prev_x*y0 - prev_y*x0
    print c, 0.5*abs(tmp)
    
   

Fixed submission:
c=0
while True:
    n=input()
    if n==0:
        break
    c+=1
    x0, y0=map(int,raw_input().split())
    prev_x, prev_y=x0, y0
    tmp=0
    for i in range(n-1):
        x,y=map(int,raw_input().split())
        tmp+=prev_x*y - prev_y*x
        prev_x, prev_y=x, y
    tmp+=prev_x*y0 - prev_y*x0
    print c, 0.5*abs(tmp)
    skip=raw_input()

Buggy python submission (verdict: Runtime Error):
c=0
while True:
    n=input()
    if n==0:
        break
    c+=1
    x0, y0=map(int,raw_input().split())
    prev_x, prev_y=x0, y0
    tmp=0
    for i in range(n-1):
        x,y=map(int,raw_input().split())
        tmp+=prev_x*y - prev_y*x
        prev_x, prev_y=x, y
    tmp+=prev_x*y0 - prev_y*x0
    print c, 0.5*abs(tmp)
    input()
    
   

Fixed submission:
c=0
while True:
    n=input()
    if n==0:
        break
    c+=1
    x0, y0=map(int,raw_input().split())
    prev_x, prev_y=x0, y0
    tmp=0
    for i in range(n-1):
        x,y=map(int,raw_input().split())
        tmp+=prev_x*y - prev_y*x
        prev_x, prev_y=x, y
    tmp+=prev_x*y0 - prev_y*x0
    print c, 0.5*abs(tmp)
    skip=raw_input()

Buggy python submission (verdict: Runtime Error):
c=0
while True:
    n=input()
    if n==0:
        break
    c+=1
    x0, y0=map(int,raw_input().split())
    prev_x, prev_y=x0, y0
    tmp=0
    for i in range(n-1):
        x,y=map(int,raw_input().split())
        tmp+=prev_x*y - prev_y*x
        prev_x, prev_y=x, y
    tmp+=prev_x*y0 - prev_y*x0
    print c, 0.5*abs(tmp)
    skip=input()
    
   

Fixed submission:
c=0
while True:
    n=input()
    if n==0:
        break
    c+=1
    x0, y0=map(int,raw_input().split())
    prev_x, prev_y=x0, y0
    tmp=0
    for i in range(n-1):
        x,y=map(int,raw_input().split())
        tmp+=prev_x*y - prev_y*x
        prev_x, prev_y=x, y
    tmp+=prev_x*y0 - prev_y*x0
    print c, 0.5*abs(tmp)
    skip=raw_input()