Counting Valleys

 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.

=============================================================================================

'use strict';

const fs = require('fs');

process.stdin.resume();

process.stdin.setEncoding('utf-8');

let inputString = '';

let currentLine = 0;

process.stdin.on('data', function(inputStdin) {

    inputString += inputStdin;

});

process.stdin.on('end', function() {

    inputString = inputString.split('\n');

    main();

});

function readLine() {

    return inputString[currentLine++];

}

/*

 * Complete the 'countingValleys' function below.

 *

 * The function is expected to return an INTEGER.

 * The function accepts following parameters:

 *  1. INTEGER steps

 *  2. STRING path

 */

function countingValleys(steps, path) {

    // Write your code here

}

function main() {

    const ws = fs.createWriteStream(process.env.OUTPUT_PATH);

    const steps = parseInt(readLine().trim(), 10);

    const path = readLine();

    const result = countingValleys(steps, path);

    ws.write(result + '\n');

    ws.end();

}