669 B | 669 chars
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
from datetime import datetime, timedelta
sys.setrecursionlimit(10**7)
BLANK = " "
# inp = input
inp = lambda : sys.stdin.readline().rstrip()
mii = lambda x = BLANK : [*map(int,inp().split(x))]
mfi = lambda x = BLANK : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def solve():
while 1:
n = ii()
if n == 0:
break
l = mii()
ans = 0
added = 0
for i in range(n - 1, -1, -1):
ans += l[i] + added
added += l[i] + added
p(ans)
if __name__ == "__main__":
tc = 1
for t in range(1, tc+1):
ret = solve()