#include<stdio.h>
int main(void){
    int n=0,month,day,a,b;
    for(month=1;month<=12;month++){
        if(month==1||month==3||month==5||month==7||month==12||month==10||month==8){
            for(day=1;day<=31;day++){
                a=day/10;
                b=day-10*a;
                if(month==a+b){
                    n++;
                    }
            }
        }
        else if(month==2){
            for(day=1;day<=28;day++){
                a=day/10;
                b=day-10*a;
                if(month==a+b){
                    n++;
                    }
            }
        }
        else{
            for(day=1;day<=30;day++){
                a=day/10;
                b=day-10*a;
                if(month==a+b){
                    n++;
                    }
            }
        }
    }
    printf("%d\n",n);
return 0;
}