#include <bits/stdc++.h>

using namespace std;

int main() {
	const int c[] = { 0,31,28,31,30,31,30,31,31,30,31,30,31 };
	int count = 0;
	for (int i = 1;i <= 12;i++) {
		for (int j = 1;j <= c[i];j++) {
			if (i == j / 10 + j % 10)
				count++;
		}
	}
	cout << count << endl;

	return 0;
}