n = int(input())
for i in range(n):
    a = [int(t) for t in list(input())]
    while len(a) != 1:
        b = []
        for j in range(len(a)-1):
            x = a[j] + a[j+1]
            if x >= 10:
                x = int(str(x)[-1]) + int(str(x)[-2])
            b.append(x)
        a = b*1
    print(a[0])