#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
    ll a = 0;
    for(ll i = 1; i <= 12; i++){
        for(ll j = 1; j <= 31; j++){
            if(i == j / 10 + j % 10 && (i != 4 || j != 31)){
                a++;
            }
        }
    }
    cout << a << endl;
}