#include 
using namespace std;

int main() {
   
    int mesec;
    cin >> mesec;
    
    if(mesec == 2) {
        cout << 28 << endl;
    }
    else if(mesec == 1 or mesec == 3 or mesec == 5 or mesec == 7 or mesec == 8 or mesec == 10 or mesec == 12) {
        cout << 31 << endl;
    }
    else {
        cout << 30 << endl;
    }
    
    
    return 0;
}