#include<iostream>
#include<string>

using namespace std;

int main(){

	int d[]={-1,31,28,31,30,31,30,31,31,30,31,30,31};
	int ans=0;

	for(int i=1;i<=12;i++){
		for(int j=1;j<=d[i];j++){
			if(i==j%10+j/10) ans++;
		}
	}

	cout<<ans<<endl;
}