#include<bits/stdc++.h> using namespace std; int main(){ int n; cin>>n; if(n==1||n==3||n==5||n==7||n==8||n==10||n==12){ cout<<"31"<<endl; } else if(n==2){ cout<<"29"<<endl; } else if(n==4||n==6||n==9||n==11){ cout<<"30"<<endl; } else{ cout<<"Invalid."<<endl; } return 0; }