#include <bits/stdc++.h>
#include <cstdint>
#include <sys/time.h>

typedef std::int_fast32_t  s32;
typedef std::uint_fast32_t u32;
typedef std::int_fast64_t  s64;
typedef std::uint_fast64_t u64;

const unsigned long mod = 1000000007;
const double EPS = 0.00000001;
const int INF = (1 << 29);

typedef std::pair<int, int> pii;

auto main() -> int
{

  std::string str;

  std::cin >> str;

  int res = 0;
  for(int i = 0; i < str.size(); ++i) {
    if( '0' <= str[i] and str[i] <= '9' ) {
      res += str[i] - '0';
    }
  }

  std::cout << res << std::endl;
  
  return 0;
}