#include <iostream>  
using namespace std;
int main() {
    int a,h=0;
    cin >> a;
    int b=a/100;
    int c=(a/10)%10;
	int d=a%10;
	h=b+c+d;
	cout<<h; 
    return 0;
}
/**************************************************************
	Problem: 1733
	User: fuhoubin
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/