#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <math.h>
#include <cmath>
#include <limits.h>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <functional>
#include <stdio.h>
using namespace std;

long long MOD = 1000000007;

int main() {
    
    int happy = 0;
    int x[4] = { 4,6,9,11 };
    
    for ( int m = 1; m <= 12; m++ ) {
        
        int D = m == 2 ? 28 : m == 4 || m == 6 || m == 9 || m == 11 ? 30 : 31;
        for ( int d = 1; d <= D; d++ ) {
            
            if ( to_string(d)[0] - '0' + to_string(d)[1] - '0' == m ) { happy++; }
            
        }
    }
    
    cout << happy << endl;
    
    return 0;
}