#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>

using namespace std;
using ll = long long;

int main()
{
	int ans = 0;
	for (int i = 1; i <= 12; i++)
	{
		int day = 0;
		switch (i)
		{
		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:
			break;
		}
		for (int j = 1; j < day + 1; j++)
		{
			if (j % 10 + floor(j / 10) == i)
			{
				ans++;
			}
		}
	}
	cout << ans << endl;
}