#include <iostream>

int main()
{
    int max_month = 12;
    int max_day;
    int ans = 0;
    for(int m=1;m<=max_month;++m){
        if(m==2){
            max_day = 28;
        }else if(m==4 || m==6 || m==9 || m==11){
            max_day = 30;
        }else{
            max_day = 31;
        }
        for(int d=1;d<=max_day;++d){
            if(m == (d/10 + d%10)){
                ans++;
            }
        }
    }
    std::cout << ans << std::endl;
}