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