#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <utility>

using namespace std;

const int SIZE = 13;
const int days[SIZE] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

int calc(int n) {
	return n / 10 + n % 10;
}

int main() {
	int happy = 0;

	for (int i = 1; i < SIZE; i++) {
		for (int j = 1; j <= days[i]; j++) {
			if (calc(j) == i) {
				happy++;
				// printf("%2d: %02d/%02d\n", happy, i, j);
			}
		}
	}

	cout << happy << endl;
	return 0;
}