#include<bits/stdc++.h>
using namespace std;
int main(){
    int ans=0;
    vector<int> day={31,28,31,30,31,30,31,31,30,31,30,31};
    for(int i=0;i<12;++i){
        for(int j=1;j<=day[i];++j){
            int k=j/10+j%10;
            if(i+1==k)++ans;
        }
    }
    cout<<ans<<endl;
}