import java.util.Scanner;

/**
 * CountingValleys
 * An avid hiker keeps meticulous records of their hikes. During the last hike
 * that took exactly steps, for every step it was noted if it was an uphill, ,
 * or a downhill, step. Hikes always start and end at sea level, and each step
 * up or down represents a
 * 
 * unit change in altitude. We define the following terms:
 * 
 * A mountain is a sequence of consecutive steps above sea level, starting with
 * a step up from sea level and ending with a step down to sea level.
 * A valley is a sequence of consecutive steps below sea level, starting with a
 * step down from sea level and ending with a step up to sea level.
 * 
 * Given the sequence of up and down steps during a hike, find and print the
 * number of valleys walked through.
 * 
 * Example
 * 
 * The hiker first enters a valley units deep. Then they climb out and up onto a
 * mountain
 * 
 * units high. Finally, the hiker returns to sea level and ends the hike.
 * 
 * Function Description
 * 
 * Complete the countingValleys function in the editor below.
 * 
 * countingValleys has the following parameter(s):
 * 
 * int steps: the number of steps on the hike
 * string path: a string describing the path
 * 
 * Returns
 * 
 * int: the number of valleys traversed
 * 
 * Input Format
 * 
 * The first line contains an integer
 * , the number of steps in the hike.
 * The second line contains a single string , of
 * 
 * characters that describe the path.
 * 
 * Constraints
 * 
 * Sample Input
 * 
 * 8
 * UDDDUDUU
 * 
 * Sample Output
 * 
 * 1
 * Explanation
 * 
 * If we represent _ as sea level, a step up as /, and a step down as \, the
 * hike can be drawn as:
 * 
 * The hiker enters and leaves one valley.
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 */
public class CountingValleys {

  // /\
  // _ / \_
  // \ /
  // \/

  public static void main(String[] args) {
    System.out.println("Please enter the number of steps: ");
    Scanner sc = new Scanner(System.in);
    int steps = sc.nextInt();
    sc.nextLine(); // consume the newline

    System.out.println("The hiker is taking " + steps + " steps starting from sea level.");
    System.out.println("Please enter the path (U for up, D for down):");
    String path = sc.nextLine();

    sc.close();
    System.out.println("Number of valleys: " + countingHikeValleys(steps, path));
  }

  private static int countingHikeValleys(int steps, String path) {
    int valleysCount = 0;
    int seaLevel = 0;
    boolean inValley = false;

    for (char step : path.toCharArray()) {
      if (Character.toUpperCase(step) == 'U') {
        seaLevel++;
      } else if (Character.toUpperCase(step) == 'D') {
        seaLevel--;
      }

      // If we're below sea level and weren't before, we're entering a valley
      if (seaLevel < 0 && !inValley) {
        valleysCount++;
        inValley = true;
      }
      // If we're at or above sea level, we're no longer in a valley
      if (seaLevel >= 0) {
        inValley = false;
      }
    }

    return valleysCount;
  }
}