#include<bits/stdc++.h>
using namespace std;
#define ll long long
typedef pair<ll,ll> P;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; } template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
#define M 1000000007
#define all(a) (a).begin(),(a).end()
#define rep(i,n) reps(i,0,n)
#define reps(i,m,n) for(int i=(m);i<(n);i++)
int main(){
  map<P,ll> m;
  rep(i,10){
    reps(j,i,10){
      ll c=i*j,d=0LL;
      while(c){
        d+=c%10;c/=10;
      }
      m[P(i,j)]=d;m[P(j,i)]=d;
    }
  }
  ll n,a,r=1LL;cin>>n;
  rep(i,n){
    cin>>a;
    while(a>=10){
      ll b=a,d=0LL;
      while(b){
        d+=b%10;b/=10;
      }
      a=d;
    }
    r=m[P(r,a)];
  }
  cout<<r <<endl;
}