import sys
input=lambda: sys.stdin.readline().rstrip()
sys.setrecursionlimit(10000)
def f(S):
  if len(S)==1:
    return S[0]
  else:
    T=[]
    for i in range(len(S)-1):
      t=S[i]+S[i+1]
      if t>=10:
        t=t%10+1
      T.append(t)
    return f(T)
x=int(input())
for _ in range(x):
  print(f([int(s) for s in list(input())]))