#include <iostream>
#include <algorithm>
#include <functional>
#include <string>
#include <climits>
#include <vector>
#include <numeric>
#include <complex>
#include <map>
#include <bitset>
#include <stack>
#include <queue>
#include <set>
using namespace std;

//#define __int64 long long
#define long __int64
#define REP(i,a,b) for(int i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)
const int Vec = 4;
const int Vecy[Vec] = {0,-1,0,1};
const int Vecx[Vec] = {1,0,-1,0};
const int Modd = 1000000007;

int main(){
	string s;
	cin >> s;
	int ans = 0;
	
	rep(i,s.length()){
		if(s[i] >= '0' && s[i] <= '9'){
			ans += (s[i] - '0');
		}
	}
	
	cout << ans << endl;
	
    
    return 0;
}