import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        
        if (!sc.hasNextInt()) return;
        int n = sc.nextInt();
        
        
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
        }
        
        
        int result = maxLength(arr);
        
        
        System.out.println(result);
    }

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