/**
 *    author:  orzvanh14 ( Độc cô cầu đặc )
 *    created: 18.04.2026 03:56:02
 *    too lazy to update time
**/
// i wants to take ioi
//binhtinhtutinkhongcaycunhungmotkhikhongcontutinnualatuyetvong
#include <bits/stdc++.h>

using namespace std;

#define int long long
#define nn "\n"
#define pi pair<int, int>
#define ti tuple<int, int, int>
#define fi first
#define se second
#define lb lower_bound
#define ub upper_bound
#define eb emplace_back
#define pb push_back
#define TASK " "

#define ms(a, x) memset(a, x, sizeof(a))
#define all(a) a.begin(), a.end()
#define All(a, n) a + 1, a + 1 + n

#define LOG 19

const int INF = 1e18;
const int N = 1e4 + 5;
const int maxn = 100 + 5;
const int mod = 1e9 + 7;


struct node{
	int kc, u;
	bool operator<(const node& other) const {
        return kc > other.kc; 
    }
};
struct edge{
	int v, w, h;
};
string s;
int cnt = 0;

void nhap(){
	cin >> s;
}
void solve(){
	for(char c : s){
            int x = c - '0';
            if(x >= 0 && x <=9) cnt++;
        }
        cout << cnt << nn;
}
signed main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	// freopen("CHONBI.INP", "r", stdin);
	// freopen("CHONBI.OUT", "w", stdout);
	nhap();
	solve();
	return 0;
}