#include <iostream>
using namespace std;
int main() {
    int x,g,s,b,_x;
    cin >> x;
    b=x/100;      
    s=(x/10)%10;    
    g=x%10;          
    _x=b+s+g;
    cout<<_x;
    return 0;
}
/**************************************************************
	Problem: 1027
	User: huangcanwu
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/