#include<bits/stdc++.h> using namespace std; int main(){ int n; cin>>n; if(n < 1|| n > 12){ cout<<"Invalid."; 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; }