#include<bits/stdc++.h> using namespace std; int main() { int n; cin>>n; switch(n){ case 1: case 3: case 5: case 7: case 8: case 10: case 12: cout<<"31"; break; case 2: cout<<"29"; break; case 4: case 6: case 9: case 11: cout<<"30"; break; default: cout<<"lnvalid."; break; } return 0; }