#include <bits/stdc++.h>
#include <atcoder/all>
#define ll long long
using namespace std;

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
    string S;
    ll cnt=0;
    cin>>S;
    for(auto c:S){
        if('0'<=c&&c<='9')cnt+=c-'0';
    }
    cout<<cnt<<endl;
}