import java.util.*;

public class Main{
  
  public static void main(String[] args){
    
    Scanner sc = new Scanner(System.in);
    
    int n = sc.nextInt();
    int[] nums = new int[n];
    
    for(int i=0; i<n; i++){
      nums[i] = sc.nextInt();
    }
    
    int ans = 0;
    
    for(int i : nums){
      boolean flag = true;
      for(int j=0; j<n; j++){
        if(i-1==nums[j]){
          flag = false;
          break;
        }
      }
      if(flag){
        ans += i;
      }
      
    }
    
    System.out.println(ans);
  
  }

}