#include <bits/stdc++.h>
using namespace std;

int main () {
    int days[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

    int count = 0;
    for (int i = 0; i < 12; i++) {
        for (int j = 0; j < days[i]; j++) {
            int a = (j + 1) / 10;
            int b = (j + 1) % 10;
            if (i + 1 == a + b) {
                count += 1;
            }
        }
    }
    cout << count << endl;
}