#include <iostream>

using namespace std;

int main() {
    int ct = 0;
    int day = 0;
    int num_sum = 0;
    
    for (int i = 1; i <= 12; i++) {
        if (i == 2) {
            day = 28;
        } else if (i == 4 || i == 6 || i == 9 || i == 11) {
            day = 30;
        } else {
            day = 31;
        }
        
        for (int j = 1; j <= day; j++) {
            num_sum = (j / 10) + (j % 10);
            if (i == num_sum) {
                ct++;
            }
        }
    }
    
    cout << ct << endl;
    
    return 0;
}