ff = open('../network.txt', 'r')
nnn = ff.readlines()
ff.close()

inf = 10 ** 10

def stolis(s):
  mid = s.split(',')
  out = []
  for i in mid:
    if i.isdigit():
      out.append(int(i))
    else:
      out.append(inf)
  return out

hole = 0
net = []
for i in nnn:
  tmp = stolis(i.strip())
  for j in tmp:
    if j < inf:
      hole += j
  net.append(tmp)

#print net

have = [0]
nothave = range(1, len(net))

total = 0
while len(nothave) > 0:
  choose = [inf, 0]
  node = 0
  it = 0
  for node in nothave:
    for it in have:
      if net[node][it] < choose[0]:
        choose = [net[node][it], node]
  if choose[0] < inf:
    have.append(choose[1])
    nothave.remove(choose[1])
    total += choose[0]

print hole / 2 - total