#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <cstring>

typedef long long ll;
using namespace std;

#define mod 1000000007
#define INF 1000000000 //(int)1e9
#define LLINF 2000000000000000000 //(ll)2e18
#define PI  3.1415926536

#define SIZE 1000

int month[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};

int main(){
    int ans = 0;
    
    for(int i=1;i<=12;i++){
        for(int j=1;j<=month[i];j++){
            
            if(i == j/10+j%10)
                ans++;
            
        }
    }
    
    printf("%d\n",ans);
    
    return 0;
}