#include<bits/stdc++.h> using namespace std; int main(){ int a; cin>>a; switch(a){ case 1: case 3: case 5: case 7: case 8: case 10: case 12: cout<<"31" ; break; case 4: case 6: case 9: case 11: break; case 2: cout<<"29" ; break; default: cout<<"Invalid." ; } return 0; }