#include<iostream>

using namespace std;

int main(){
    int t=0,x=0;
  for(int i = 1; i <= 12;i++){
    switch(t){
      case 2:
        t=28;
        break;
      case 4:
      case 6:
      case 9:
      case 11:
        t = 30;
        break;
      default:
        t = 31;
        break;}
      for(int j = 1; j <= t; j++){
        if(i == (j/10)+(j%10))
          x++;
      }
}
cout << x << endl;
return 0;}