#include <bits/stdc++.h>

using namespace std;
using vi = vector<size_t>;
using ull = unsigned long long;
using ll = long long;

ull modmul(ull a, ull b, ull M){
    ll ret = a * b - M * ull(1.L/M*a*b);
    return ret + M * (ret<0) - M * (ret >= (ll)M);
}

ull modpow(ull b, ull e, ull mod){
    ull ans =1;
    for (; e; b = modmul(b,b,mod), e/=2)
        if(e & 1) ans = modmul(ans, b, mod);
    return ans;
}

bool isPrime(ull n){
    if (n<2 || n % 6 % 4 !=1) return (n | 1) == 3;
    ull A[] = {2, 325, 9375, 28178, 450775, 9780504, 1795265022},
        s = __builtin_ctzll(n-1), d =  n>>s;
    for (ull a : A){
        ull p = modpow(a%n, d, n), i =s;
        while (p != 1 && p != n-1 && a %n && i--)
            p= modmul(p,p,n);
        if(p!=n-1 && i != s) return false;
    }
    return true;
}


ll next (string str){
    if(!str.size())
        return 0;
    ll res = 0;
    ull n =stoull(str);
    if(isPrime(n)){
        str = to_string(n);
        res++;
        ll maxn = 0;
        for(ll i = 0 ; i < str.size(); i++){
            string tmp = str;
            maxn = max(next(tmp.erase(i, 1)), maxn);
        }
        res += maxn;
    }
    else {
        return 0;
    }
    return res;
}

void solve(){
    ll num;
    cin >> num;
    cout << next( to_string(num));
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);
    int t = 1;
    //cin >> t;
    while (t--){
        solve();
    }
    return 0;
}