#include <bits/stdc++.h>

using namespace std;


#define int long long

signed main(){

    int n; cin >> n;
    vector<int> v; 
    int p = 0;

    for (int i = 1; i <= n; i++){
        int a; cin >> a; 
        a = a + p;
        v.push_back(a%10);
        p = a/10;
    }
    while (p > 0){
        v.push_back(p%10);
        p /= 10;
    }
    


    int x = 0;
    for (int i = v.size()-1; i >= 0; i--){
        if (v[i] != 0){
            x = i;
            break;
        }
    }

    cout << (to_string(v[x]))+string(x, '0') << endl;




/*
    //reverse(v.begin(), v.end());

    int mego = v[n-1]; // lehet 0

    for (int i = n-2; i >= 0; i--){
        //cout << n-i-1 << " " << v[i]/10 << endl;
        if (v[i] / 10 >= n-i-1){
            mego += v[i]/10;
            break;
        }
    }

    

    cout << (to_string(mego))+string(n-1, '0');
*/
    return 0;
}