a=int(input())
b=a//1000
c=a//100%10*10
d=a//10%10*100
e=a%10*1000
f=e+d+c+b
print(a-f)
/**************************************************************
	Problem: 1702
	User: admin
	Language: Python
	Result: Accepted
	Time:93 ms
	Memory:34244 kb
****************************************************************/