#include <iostream>
#include<math.h>
using namespace std;
using ll = long long;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main()
{
    int r = 0;
    for (int i = 1; i <= 12; i++) {
        int d;
        if (i == 2) d = 28;
        else if (i == 1 || i == 3 || i == 5 || i == 7 || i == 8 || i == 10 || i == 12) {
            d = 31;
        }
        else{
            d = 30;
        }

        for (int j = 1; j <= d; j++) {
            if (i == (j / 10) + (j % 10)) r++;
        }
    }
    cout << r << endl;
    return 0;
}