#include<bits/stdc++.h>
using namespace std;
int main()
{
int x,y,z,s,a;
cin>>x;
z=x%10;
y=x/10%10;
a=x/100;
s=y+z+a;
cout<<s;
	return 0;
}

/**************************************************************
	Problem: 1027
	User: zxh001
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/