#include <iostream>
using namespace std;

bool isHappy(int mon,int day);

int main(void){
//calc
	int cnt=0; bool happy;
	
	for(int mon=1;mon <= 12;mon++){
		if(mon == 2){
			for(int j=1;j<=28;j++){
				happy = isHappy(mon,j);
				if(happy) cnt++;
			}
		}else if(mon == 4 || mon == 6 || mon == 9 || mon == 11){
			for(int j=1;j<=30;j++){
				happy = isHappy(mon,j);
				if(happy) cnt++;
			}
		}else{
			for(int j=1;j<=31;j++){
				happy = isHappy(mon,j);
				if(happy) cnt++;
			}
		}
	}
//output
	cout << cnt;
}

bool isHappy(int mon,int day){
	
	int day_sum = (day / 10) + (day % 10);
	
	if(day_sum == mon){
		return true;
	}else{
		return false;
	}
}