#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
    int count = 0;
    for(int i = 1;i <= 12;i++){
        for(int j = 1;j < 31;j++){
            if(i == j/10 + j%10)count++;
        }
    }
    cout << count << endl;
    return 0;
}