#include <iostream>

using namespace std;

typedef unsigned char SmallNum; /* 0~255 */
SmallNum month_ranges[] = {
	31,28,31,30,31,30,31,31,30,31,30,31
};

int main(void) {
	size_t happy_days = 0;
	for (SmallNum i = 1; i <= 12; ++i) {
		SmallNum const end = month_ranges[i - 1];
		for (SmallNum day = 1; day <= end; ++day) {
			if (i == (day / 10) + (day % 10))
				happy_days++;
		}
	}

	cout << to_string(happy_days) << endl;

	return 0;
}