#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"; } else if (n == 4 || n == 6 || n == 9 || n == 11) { cout << "30"; } else if (n == 2) { cout << "29"; } else { cout << "lnvalid."; } }