#include <bits/stdc++.h>
using namespace std;
#define ll long long
string s[100005];
int main()
{
    ios_base::sync_with_stdio(false);
    int n;
    string ans;
    int id;
    int flag1 = 0;
    int i;
    int m;
    int flag = 0;
    int cnt = 0;
    int j;

    cin>>n;
    for(j = 0; j < n; j++) {
        cin>>s[j];
        m = s[j].size();
        if(m == 1 && s[j][0] == '0') {
            cout << "0";
            return 0;
        }
        cnt = 0;
        if(flag1 == 0) {
        for(i = 0; i < m; i++) {
            if(s[j][i] == '1') {
                cnt++;
                if(cnt >= 2) {
                    id = j;
                    ans = s[j];
                    flag1 = 1;
                    break;
                }
            }
            else if(s[j][i] != '0' && s[j][i] != '1') {
                id = j;
                ans = s[j];
                flag1 = 1;
                break;
            }
        }
        }
    }
    cnt = 0;
    if(flag1 == 0) {
        ans = s[0];
        id = 0;
    }
    for(i = 0; i < n; i++) {
        m = s[i].size();
        if(id != i) {
            for(j = 0; j < m; j++) {
                if(s[i][j] == '0') {
                    cnt++;
                }
            }
        }
    }
    if(flag == 1) {
        cout<<0;
    }
    else {
        cout<<ans;
        for(i = 0; i < cnt; i++) {
            printf("%d",0);
        }
    }
}