#include <stdio.h>
#include <stdlib.h>

int compare_int( const void*a, const void*b){
	int ta = *(int*)a;
	int tb = *(int*)b;
	return ta - tb; // tb-taだと降順
}


int main(void){
	int i,j,n;
	int student[60]={0};
	int row[60] = {0};
	scanf("%d", &n);
	for(i=0;i<n;i++){
		int a;
		scanf("%d", &a);
		student[i] = i*100 + a;
	}
	
	for(i=0;i<n;i++){
		int Idislike = student[i]%100;
		int flag = 1;
		
		if( i != Idislike ){continue;}
		
		for(j=0;j<n;j++){
			int tmp;
			int Jdislike = student[j]%100;
			if(i == j){continue;}
			if(Jdislike == i){continue;}
			if(Idislike == j){continue;}
			tmp = student[j];
			student[j] = student[i];
			student[i] = tmp;
			
			flag = 0;
			break;
		}
		
		if( flag == 1 ){
			student[0] = -1;
			break;
		}
	}
	
	if(student[0] == -1){
		printf("%d\n", student[0]);
	}else{
		for(i=0;i<n;i++){
			int Ino = student[i]/100;
			row[i] = Ino * 100 + i;
		}
		
		qsort(row, n, sizeof(int), compare_int);
		for(i=0;i<n;i++){
			printf("%d\n", row[i]%100);
		}
	}
	
	
	return 0;
}