content: import java.io.*;
  import java.math.*;
  import java.security.*;
  import java.text.*;
  import java.util.*;
  import java.util.concurrent.*;
  import java.util.regex.*;
  
  public class Solution {
  
    // Complete the minimumDistances function below.
    static int minimumDistances(int[] a) {
      int min = Integer.MAX_VALUE;
      HashMap<Integer, Integer> dp = new HashMap<>();
      for (int i = 0; i < a.length; i++) {
        if (dp.containsKey(a[i])) {
          min = Math.min(
              min,
              i - dp.get(a[i])
          );
        } else {
          dp.put(a[i], i);
        }
      }
  
      return (min == Integer.MAX_VALUE) ? -1 : min;
    }
  
    private static final Scanner scanner = new Scanner(System.in);
  
    public static void main(String[] args) throws IOException {
      BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));
  
      int n = scanner.nextInt();
      scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");
  
      int[] a = new int[n];
  
      String[] aItems = scanner.nextLine().split(" ");
      scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");
  
      for (int i = 0; i < n; i++) {
        int aItem = Integer.parseInt(aItems[i]);
        a[i] = aItem;
      }
  
      int result = minimumDistances(a);
  
      bufferedWriter.write(String.valueOf(result));
      bufferedWriter.newLine();
  
      bufferedWriter.close();
  
      scanner.close();
    }
  }
  