#include <iostream>
#include <string>

using namespace std;
int main(void){

    int count = 0;
    for(int month = 1; month <= 12; month++) {
        int max_day;
        if(month == 2) {
            max_day = 28;
        }
        else if(month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12) {
            max_day = 31;
        }
        else {
            max_day = 30;
        }
        for(int day = 1; day <= max_day; day++) {
            if(month == ((day/10) + (day%10))) {
                count++;
            }
        }
    }
    
    cout << count << endl;

    return 0;

}