t = int(input())
for _ in range(t):
    s = list(str(input()))
    s = [int(i) for i in s]
    while len(s) > 1:
        temp = []
        for i in range(len(s)-1):
            if s[i]+s[i+1] < 10:
                temp.append(s[i]+s[i+1])
            else:
                temp.append(1+(s[i]+s[i+1])%10)
        s = temp
    print(s[0])