#include <iostream>

using namespace std;

int main() {
    int i, i1, i2, count = 0;
    for (i = 1; i <= 28; i++) {
        i1 = i/10;
        i2 = i%10;
        int i3 = i1 + i2;
        if (i3 <= 12) {
            count++;
        }
    }
    count += 2;
    cout << count << endl;
    return 0;
}