n=int(input())
ans=[]
for k in range(n):
    s=list(map(int,input()))
    ls=[]
    ls.append(s)
    for j in range(len(ls[0])-1):
        s=[]    
        for i in range(len(ls[j])-1):
            buf=ls[j][i]+ls[j][i+1]
            if  buf>=10:
                s.append(1+buf%10)
            else:
                s.append(buf)
        ls.append(s)
    ans.append(ls[-1][0])
for s in ans:
    print(s)