#include<bits/stdc++.h>
using namespace std;
 
int main(){
int a,s,d,f,j;
cin>>a;
s=a%10;
d=a/10%10;
f=a/100;
j=s+d+f;
cout<<j;
    return 0;
}
/**************************************************************
	Problem: 1027
	User: 12345678
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/