#include <iostream>

using namespace std;

int main()
{
    int month = 0;
    int day = 0;
    int cnt_happyday = 0;

    for( month = 1; month <= 12; month++)
    {
        if( month == 4 || month == 6 || month == 9 || month == 11 )
        {
            for( day = 1; day <=30; day++ )
            {
                if( month == ( day / 10 + day % 10 ) )  cnt_happyday++;
            }
        }

        else if( month == 2 )
        {
            for( day = 1; day <=28; day++ )
            {
                if( month == ( day / 10 + day % 10 ) )  cnt_happyday++;
            }
        }

        else
        {
            for( day = 1; day <= 31; day++ )
            {
                if( month == ( day / 10 + day % 10 ) )  cnt_happyday++;
            }
        }
    }

    cout << cnt_happyday << endl;

    return 0;
}