#include <stdio.h>

int main(void) {
	int month, day, count, temp;
	count = 0;

	for (month = 1;month <= 12;month++) {
		for (day = 1;day < 10; day++) {
			if (month == day) count++;
		}
		
		for (day = 10;day < 31;day++) {
			temp = day / 10 + day % 10;
			if (month == temp) count++;
		}
	}

	printf("%d", count);

	return 0;
}