// No.289 数字を全て足そう
// https://yukicoder.me/problems/no/289
//

using namespace std;
#include <iostream>

int solve(string &S);

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

    int ans = solve(S);
    cout << ans << endl;
}

int solve(string &S) {
    int ans = 0;
    for (char c: S) {
        if (isdigit(c)) {
            ans += c - '0';
        }
    }
    return ans;
}