#include <iostream>
using namespace std;
int main(){
   int M;
   1<=M<=12;
   cin >> M;
   if(M == 1 or M == 3 or M == 5 or M == 7 or M == 8 or M == 10 or M == 12) {
       cout << "31" <<endl;
   }
   if(M == 2) {
       cout << "28" <<endl;
   }
   if(M == 4 or M == 6 or M == 9 or M == 11) {
       cout << "30" <<endl;
   }
   return 0;}