#include<stdio.h>
#include<stdlib.h>
void merge(int arr[],int left,int mid,int right){
    int n1=mid-left+1;
    int n2=right-mid;
    int L[n1],R[n2];
    for(int i=0;j<n1;j++)
    L[i]=arr[left+i];
    fr(int j=0;j<n2;j++)
    R[j]=arr[mid+1+j];
    int i=0,j=0,k=left;
    while(i<n1&&j<n2){
        if(L[i]<=R[j]){
            arr[k]=L[i];
            i++;
        }else{
            arr[k]=R[j];
            j++;
        }
        k++;
    }
    while(i<n1){
        arr[k]=L[i];
        i++;
        k++;
    }
    while(j<n2){
        arr[k]=R[j];
        j++;
        k++;
    }
}
void mergesort(int arr[],int left,int right){
    if(left<right){
        int mid=(left+right)/2;
        mergesort(arr,left,mid);
        mergesort(arr,mid+1,right);
        merge(arr,left,mid,right);
    }
}
int main(){
    int n;
    scanf("%d",&n);
    if(n<1 || n>100){
        printf("Invalid input");
        return 0;
    }
    int arr[n];
    int negative=0;
    for(int i=0;i<n;i++){
        scanf("%d",&arr[i]);
        if(arr[i]<0)
        negative=1;
    }
    if(negative){
        printf("Invalid input");
        return 0;
    }
    int sorted=1;
    for(int i=0;i<n-1;i++){
        if(arr[i]>arr[i+1]){
            sorted=0;
            break;
        }
    }
    if(sorted){
        printf("-1");
        return 0;
    }
    mergesort(arr,0,n-1);
    for(int i=0;i<n;i++){
        printf("%d",rr[i]);
    }
    return 0;
}