#include<iostream> #include<cstdio> #include<cstring> #include<cmath> #include<iomanip> using namespace std; int main() { int a; cin>>a; int a1,a2,a3,a4; a1=a%10; a2=a/10%10; a3=a/100%10; a4=a/1000%10; cout<<a4+a1+a2+a3+endl; return 0; }