import sequtils, strutils, sugar


func fn1(s: string): int =
  var ns = s.toSeq.mapIt ($it).parseInt
  while ns.len > 1:
    let
      a = ns[0..^2]
      b = ns[1..^1]
    var
      list: seq[int]
    for i in 0 .. a.high:
      var
        x = a[i] + b[i]
      if x >= 10:
        x = x mod 10 + 1
      list.add x
    ns = list
  return ns[0]


let
  t = parseInt stdin.readLine
  ss = newSeq.collect:
    for _ in 0 ..< t: stdin.readLine

for s in ss:
  echo s.fn1