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