#include<bits/stdc++.h> using namespace std; int main(){ int n; cin >> n; if (n<=0 && n>=12) cout << "Invalid."; if (n==1){ cout << "31"; }else if (n==2){ cout << "29"; }else if (n==3){ cout << "31"; }else if (n==4){ cout << "30"; }else if (n==5){ cout << "31"; }else if (n==6){ cout << "30"; }else if (n==7){ cout << "31"; }else if (n==8){ cout << "31"; }else if (n==9){ cout << "30"; }else if (n==10){ cout << "31"; }else if (n==11){ cout << "30"; }else{ cout << "31"; } return 0; }