#include <bits/stdc++.h>
using namespace std;
//#pragma GCC optimize ("-O3")
using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
using pi = pair<int, int>;
using pl = pair<ll, ll>;
const char alphabetl[26] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};
const char alphabetu[26] = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};
const ll MOD = (ll) 1e9 + 7;
const int MAX_INT = 1 << 17;
const ll INFL = 1LL << 60;

const ll MAX_V = 1010;
const ll MAX_E = 2010;
ll V, E;
struct edge {
    ll from, to, cost;
};
edge ES[MAX_E];
ll d[MAX_V];

#define ALL(obj) (obj).begin(),(obj).end()
#define RALL(obj) (obj).rbegin(),(obj).rend()
#define PRINT(n) cout << n << "\n";
#define PRINT2(n, m) cout << n << " " << m << " "<< "\n";

// REP(i,n)   -- 0 - n-1 ++
#define REP(i,n)  for(int i=0;i<(int)n;++i)
// RREP(i,n)  -- n-1 - 0 --
#define RREP(i,n) for(int i =(int)n;i>0;--i)
// rep(i,a,b) -- a - b   ++
#define rep(i,a,b) for(int i=a;i<=b;i++)
// rrep(i,a,b)-- a - b   --
#define rrep(i,a,b) for(int i=a;i>=b;i--)

// 0 - 2^(n-1)
#define REPbit(bit, n)  for(int bit = 0; bit < (int)(1<<n); ++bit)
#define FOR(i,a,b)  for(int i=a; i<=(int)b; ++i)
void no289();
int main() {cin.tie(0); ios::sync_with_stdio(false); no289();}

/********************************/
/** yukicoder No.289           **/
/** by MoonlightSonata         **/
/********************************/

void no289(){
    string s;
    int ans = 0;
    cin >> s;
    for(auto& i : s)
        if (isdigit(i)) ans += i-'0';
    PRINT(ans)
}