#define _USE_MATH_DEFINES
#include<iostream>
#include<vector>
#include<cstdio>
#include<string>
#include<algorithm>
#include <iomanip>
#include<cmath>
#include<numeric>
#include<map>
#include<stack>
using namespace std;

#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define all(a) (a).begin(),(a).end()

typedef long long ll;
typedef vector<int> vi;
typedef vector<double> vd;

int i, j, k;

int main()
{
    string s; int ans = 0;
    cin >> s;
    REP(i, s.size())
    {
        if (s[i] >= '0' && s[i] <= '9')
        {
            ans += s[i] - '0';
        }
    }
    cout << ans << endl;
}