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

int main() {
    int day[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
    int hd = 0;
    for (int m = 1; m <= 12; m++) {
        int nd = day[m-1];
        for (int d = 1; d <= nd; d++) {
            int sum = d / 10 + d % 10;
            if (m == sum) hd++;
        }
    }
    cout << hd << endl;
}