#include <bits/stdc++.h>
using namespace std;

int main() {
    vector<int> days={31,28,31,30,31,30,31,31,30,31,30,31};
    int ans=0;
    for(int i=0;i<12;i++){
        for(int j=1;j<=days[i];j++){
            if(i==j/10+j){
                ans++;
            }
        }
    }
    cout << ans << endl;
    return 0;
}