/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner sc = new Scanner(System.in);
		int size = sc.nextInt();
 
		int[] arr =new int[size];

		for(int i = 0;i<size;i++){
			arr[i] = sc.nextInt();
		}

		
 
            int result = maxLength(arr);
            System.out.println(result);
        

	}
	public static int maxLength(int arr[]) {
        HashMap<Integer, Integer> present = new HashMap<>();
        
        int n = arr.length;
        int[] prefixSum = new int[n];
        int sum = 0;
        
        
        for (int i = 0; i < n; i++) {
            sum += arr[i];
            prefixSum[i] = sum; 
        }
        present.put(0, -1);
        int maxLongestSubArray = 0;
        
        
        for (int i = 0; i < n; i++) {
            int num = prefixSum[i];
            
           
            if (num == 0) {
                maxLongestSubArray = Math.max(maxLongestSubArray, i + 1);
            }
            
            
            if (present.containsKey(num)) {
                int currentLongestSubArray = i - present.get(num);
                maxLongestSubArray = Math.max(currentLongestSubArray, maxLongestSubArray);
            } else {
                
                present.put(num, i);
            }
        }
        
        return maxLongestSubArray;
    }
}