#include<stdio.h>
int main(void){
	int m, day, td, d, flag, hp=0;
	for(m=1; m<=12; m++){
		switch(m){
			case 2:
			flag = 28;
			break;
			
			case 4:
			case 6:
			case 9:
			case 11:
			flag = 30;
			break;
			
			default:
			flag = 31;
		}
		for(day=1; day<=flag; day++){
			td = day / 10;
			d = day % 10;
			if((td + d) == m){
			hp++;}
		}
	}
	printf("%d\n", hp);
}