// Enter your code here 

//var n:Int = readLine() as! Int
var n:Int = Int(readLine()!)!
var steps: String = readLine()!

let seaLevel = 0
var currentLevel = seaLevel
var valleyCount = 0
var isDown = false

for step in steps.characters {
    if step == "D" {
        currentLevel -= 1
        if currentLevel < 0 { isDown = true }
    } else {
        currentLevel += 1
    }
    
    if isDown == true && currentLevel == 0 {
        isDown = false
        valleyCount += 1
    }
}

print(valleyCount)