import java.util.*;
public class Zd15 {
    public static void main(String[] args) {
        long timestart=System.currentTimeMillis();
        Scanner sc = new Scanner(System.in);
        int k = sc.nextInt();
        String s = sc.next();
        int[] a = stringToBig(s);
        for (int i = 0; i < k-1; i++) {
            String c = sc.next();
            int[] b = stringToBig(c);
            a=proizv(a,b);
        }

        long timeend=System.currentTimeMillis() ;
        System.out.println("THIS TIME "+ (timeend-timestart));
        out(a);

    }
    public static int[] stringToBig(String c){
                    int[] b = new int[c.length()];//остальные члены
            for (int j = 0; j < c.length(); j++) {
                b[j] = (c.charAt(j)- '0');
            }
        return  b;
    }
    public static int[] proizv(int[] a, int[] b) {
        int[] c = new int[a.length + b.length];
        boolean used[] = new boolean[c.length];
        for(int i = a.length - 1;i >= 0; i--) {
            for (int j = b.length - 1; j >= 0; j--) {
                c[i + j] += a[i] * b[j];
                c[i+j+1]= c[i+j]/10;
                c[i+j]%=10;
                used[(i + j)] = true;
            }
        }

        if (!used[c.length - 1] && c[0] / 10 == 0){
            int[] tmp = c;
            c = new int[c.length - 1];
            for (int k = 0; k < c.length; k++)
                c[k] = tmp[k];
        }
        int d = 0;
        if (c[0] / 10 > 0){
            for (int k = c.length - 1; k > 0; k--)
                c[k] = c[k - 1];
            c[0] = 0;
        }
        return c;
    }
    public static void out(int[] a) {
        System.out.println();
        for (int val : a) {
            System.out.print(val);
        }
    }

}