#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>
using namespace std;

int main()
{
	int x, y, day;
	int cnt = 0;
	for (int x = 1; x <= 12; x++) {
		switch (x) {
			case 1:
			case 3:
			case 5:
			case 7:
			case 8:
			case 10:
			case 12:
				day = 31;
				break;
			case 2:
				day = 28;
				break;
			case 4:
			case 6:
			case 9:
			case 11:
				day = 30;
				break;
			default:
				return 1;
		}

		for (int y = 1; y <= day; y++) {
			if (x == (y / 10 + y % 10)) {
				// cout << x << "月" << y << "日" << endl;
				cnt++;
			}
		}
	}
	cout << cnt << endl;

	return 0;
}