#fourth def f(n,x):          a=[0,1,2,3,4,5,6,7,8,9,'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z']     b=[]     while True:         s=n//x           y=n%x           b=b+[y]         if s==0:             break         n=s     b.reverse()     data=[]     for i in b:         data.append(str(a[i]))     return "".join(data) number = int(input()) for i in range(number):     jinzhi = int(input())     values = list(map(str,input().split()))     value1 = int(values[0], jinzhi)     value2 = int(values[1], jinzhi)     value3 = values[2]     if value3 == "+":         final = value1 + value2         print(f(final, jinzhi))     elif value3 == "-":         final = value1 - value2         print(f(final, jinzhi))     elif value3 == "*":         final = value1 * value2         print(f(final, jinzhi))      第四道题投机取巧AC，求第三道题AC的