#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef pair<int,int> P;
 
const int INF = 1e9;
const int mod = 1e9+7;
const double EPS = 1e-10;
const double PI = acos(-1.0);
 
int main()
{
    int ans = 0;
    int a[] = {0,31,28,31,30,31,30,31,31,30,31,30,31};
    for(int i = 1; i <= 12; i++){
        for(int j = 1; j <= a[i]; j++){
            if(i == j/10+j%10) ans++;
        }
    }
    cout << ans << endl;
    return 0;
}