import java.util.Scanner;
import java.util.Arrays;

public class Main {
  public static void main(String[] args) {
    task5();
  }

  static void task5() {
    Scanner sc = new Scanner(System.in);
    long count = 0;

    while (sc.hasNextLine()) {
        String line = sc.nextLine();
        int wordLen = 0;
        char lastChar = 0;

        for (int i = 0; i < line.length(); i++) {
            char ch = line.charAt(i);

            if (Character.isLetter(ch)) {
                wordLen++;
                lastChar = ch;
            } else {
                if (wordLen == 1 && (lastChar == 'a' || lastChar == 'A')) {
                    count++;
                }
                wordLen = 0;
            }
        }

        if (wordLen == 1 && (lastChar == 'a' || lastChar == 'A')) {
            count++;
        }
    }

    sc.close();
    System.out.println(count);
  }


  static void task4() {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    sc.nextLine();
    String s = sc.nextLine();
    sc.close();

    int count = 0;

    for (char ch : s.toCharArray()) {
      if (ch == 'a') {
        count++;
      }
    }

    System.out.println(count);
  }

  static void task3() {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    sc.nextLine();

    int[] rows_sum = new int[n];
    int[] columns_sum = new int[n];
    Arrays.fill(columns_sum, 0);

    int[][] mat = new int[n][n];
    for (int i = 0; i < n; i++) {

      int row_sum = 0;

      String[] srow = sc.nextLine().split(" ");
      int[] row = new int[n];
      for (int j = 0; j < n; j++) {
        row[j] = Integer.parseInt(srow[j]);
        row_sum += row[j];
        columns_sum[j] += row[j];
      }

      mat[i] = row;
      rows_sum[i] = row_sum;
    }

    sc.close();

    // for (int i = 0; i < n; i++) {
    //   System.out.println(Arrays.toString(mat[i]));
    // }

    // System.out.println("rows sum: " + Arrays.toString(rows_sum));
    // System.out.println("columns sum: " + Arrays.toString(columns_sum));

    int interesting_pairs = 0;

    for (int i = 0; i < n; i++) {
      for (int j = 0; j < n; j++) {
        if (Math.abs(rows_sum[i] - columns_sum[j]) <= mat[i][j]) {
          interesting_pairs++;
        }
      }
    }

    System.out.println(interesting_pairs);
  }

  static void task2() {
    Scanner sc = new Scanner(System.in);
    long n = sc.nextInt();
    sc.close();
    System.out.println(n == 1 ? 1 : 4 * (n - 1));
  }

  static void task1() {
    Scanner sc = new Scanner(System.in);
    long n = sc.nextInt();
    sc.close();
    long s = ((100 + n) * (n - 99)) / 2;
    System.out.println(s);
  }
}