#include<iostream>
using namespace std;

int main(){
				int hd = 0;
				for(int i = 1; i <= 12; i++){
								int d;
								if(i == 1 or i == 3 or i == 5 or i == 7 or 
										i == 8 or i == 10 or i == 12) d = 31;
								else if(i == 2) d = 28;
								else d = 30;
								for(int j = 1; j <= d; j++){
												if( i == j/10 + j%10) hd++;
								}
					}
				cout << hd << endl;
		return 0;
}