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