content: import java.util.Scanner;
  
  /* Idea: Use a "sliding window" of "m" squares. Each time we add a square to the right, remove one from the left. */
  /* https://www.hackerrank.com/challenges/the-birthday-bar/problem */
  
  //  Time Complexity: O(n)
  // Space Complexity: O(1) (other than saving input)
  public class Solution {
      static int solve(int n, int[] square, int d, int m) {        
          int sum = 0;
          int numWays = 0;
          
          /* Test first set of "m" chocolates */
          for (int i = 0; i < m; i++) {
              sum += square[i];
          }
          if (sum == d) {
              numWays++;
          }
          
          /* Test remaining sets of "m" chocolates */
          for (int i = m; i < square.length; i++) {
              sum += square[i] - square[i-m]; // add chocolate, remove chocolate
              if (sum == d) {
                  numWays++;
              }
          }
          
          return numWays;
      }
  
      public static void main(String[] args) {
          /* Save input */
          Scanner scan = new Scanner(System.in);
          int n = scan.nextInt();
          int[] square = new int[n];
          for (int i = 0; i < n; i++) {
              square[i] = scan.nextInt();
          }
          int d = scan.nextInt();
          int m = scan.nextInt();
          scan.close();
          
          /* Calculate result */
          int result = solve(n, square, d, m);
          System.out.println(result);
      }
  }
  
  