#include<iostream>
using namespace std;
int main(){
    int i,j,ans;
    int c[13]={0,31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
    for(i=1;i<=12;i++){
        for(j=1;j<=c[i];j++){
            if(i==j/10+j%10) ans++;
        }
    }
    cout << ans <<endl;
}