# Input: lines like "<code>-<code>"
# Output: how many sets of three codes are connected to each other,
#         and at least one starts with "t"?

connections = {}

file = open("23_input.txt", "r")
for line in file:
  line = line.replace("\n", "")
  parts = line.split("-")
  if not (parts[0] in connections):
    connections[parts[0]] = []
  connections[parts[0]].append(parts[1])
  if not (parts[1] in connections):
    connections[parts[1]] = []
  connections[parts[1]].append(parts[0])

total = 0
for code in connections:
  if code[0] == "t":
    other_codes = connections[code]
    for i in range(len(other_codes) - 1):
      if other_codes[i][0] == "t" and other_codes[i] < code:
        continue
      for i2 in range(i + 1, len(other_codes)):
        if other_codes[i2][0] == "t" and other_codes[i2] < code:
          continue
        if other_codes[i] in connections[other_codes[i2]]:
          total += 1
print (total)