#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
#include <stack>
using namespace std;

#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)
#define SQR(X) ((X)*(X))

typedef long long ll;
typedef unsigned long long ull;
typedef long double lb;
/* ここからが本編 */

int main(void)
{
   int i,j;
   char s[10005];
   int sum = 0;
   cin >> s;
   for(i = 0;s[i];i++) {
      if('0' <= s[i] && s[i] <= '9') sum += s[i] - '0';
   }
   cout << sum << endl;
   return 0;
}