#include<stdio.h>
int main(){
    int N;
    scanf("%d",&N);
    if (N < 0) {
        printf("Invalid Input");
        return 0;
    }
    int arr[N];
    for (int i = 0; i < n; i++) {
        scanf("%d",&arr[i]);
    }
    int result[N];
    int index = 0;
    for (int i = 0 ; i < N; i++){
        if (arr[i] != 0) {
            result[index++] = arr [i];
        }
    }
    while (index < N) {
        result[index++] = 0;
    }
    for (int i = 0; i < N; i++){
        printf("%d", result[i]);
    }
    return 0;
}