#include <iostream>

using namespace std;

int main(){
  int i;
  int maxday;
  int d1, d2;
  int count = 0;
  for (i = 1;i <= 12;i++){
      if (i==2){
        maxday = 28;
      }else if (i==1||i==3||i==5||i==7||i==8||i==10||i==12){
        maxday = 31;
      }else{
        maxday = 30;
      }
      for (int day = 1;day<=maxday;day++){
        d1 = day % 10;
        d2 = day / 10;

        if (i == (d1+d2)){
          count++;
          //cout << "month:"<<i<<" day:"<<day<<endl;
        }
      }
  }
  cout << count << endl;
}