xu=2134
su=4123
def bian():
XU=[]
XU+=[xu//1000]
XU+=[xu//100%10]
XU+=[xu%100//10]
XU+=[xu%10]
SU=[]
SU+=[su//1000]
SU+=[su//100%10]
SU+=[su%100//10]
SU+=[su%10]
cu=0
print(XU,SU)
for a in range(4):
cu=cu+XU[a]*(10**(4-SU[a]))
print(cu)
bian()
print(cu)