#include <bits/stdc++.h>

using namespace std;

#define out(x) cout << #x << '=' << x << endl
#define out2(x, y) cout << #x << '=' << x << ',' << #y << '=' << y << endl 
#define no cout << "No" << endl; return
#define yes cout << "Yes" << endl; return
#define outvec(a) for (int v : a) { cout << v << ' '; } cout << endl
#define lowbit(x) (x & -x)
#define gcd __gcd 
#define inf 0x3f3f3f3f3f3f3f3fLL
#define infi 0x3f3f3f3f

using ll = long long;
using pii = pair<int, int>;


void solve() {
	int n;
	string s;
	cin >> n >> s;
	int sum = 0;
	for (int i = 0; i < n; i++) {
		sum += s[i] - '0';
	}
	int ans = 0;
	for (int i = 0; i < n; i++) {
		int k = s[i] - '0';
		for (int j = 0; j < 10; j++) {
			if (j == k) continue;
			if ((sum - k + j) % 9 == 1) {
				ans++;
			}
		}
	}
	cout << ans << endl;
}

int main(void) {
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    int t = 1;
    //cin >> t;
    
    while (t--) {
    	solve();
	}
}