let n = Int(readLine()!)!
var sx = [String]()

var result = Set<String>()

for _ in 0..<n {
  sx.append(readLine()!)
}

for i in 0..<n {
  for j in 0..<n {
    if i == j { continue }
    result.insert(sx[i] + sx[j])
  }
}

print(result.count)