def l(x):
	while len(x)>1:x=[[0,1,2,3,4,5,6,7,8,9,1,2,3,4,5,6,7,8,9][x[i]+x[i+1]]for i in range(len(x)-1)]
	return x[0]
for _ in[0]*int(input()):print(l(list(map(int,input()))))