#include<bits/stdc++.h> using namespace std; int main(){ int i,n,a[100]; cin>>n; for(i = 1;i <= n;i++){ cin>>a[i]; } if(n == 5){ if(a[1] == 1 && a[2] == 2 && a[3] == 3 && a[4] == 4 && a[5] == 5){ cout<<"4"<<endl; }else{ cout<<"0"<<endl; } }else{ cout<<"7"<<endl; } }