#include "bits/stdc++.h"
using namespace std;
using Graph = vector<vector<int>>;
typedef long long ll;
typedef pair<ll, ll> P;
#define rep(i,n) for (ll i = 0; i < (n); ++i)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
const long long mod = 1e9 + 7;

ll gcd(ll a, ll b) {
	return b ? gcd(b, a % b) : a;
}

ll lcm(ll a, ll b) {
	return a / gcd(a, b) * b;
}

int main() {
	ll ans=0;
	
	vector<ll> m ={31,28,31,30,31,30,31,31,30,31,30,31};

	for (ll i = 0; i < 12 ; ++i) {
		for (ll j = 1; j <= m[i]; j++) {
			if (i + 1 == j / 10 + j % 10) {
				ans++;
			}
		}
	}
	cout << ans << endl;
}