#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 MIN(a, b) (a > b ? b : a)
#define MAX(a, b) (a > b ? a : b)

#include <bits/stdc++.h>

using namespace std;

int main() {
    string S;
    cin >> S;

    long ans = 0;

    REP(i, S.size()) {
        if (isdigit(S[i])) {
            ans += S[i] - '0';
        }
    }

    cout << ans << endl;

    return 0;
}