object Main extends App {
  var a = readInt
  var get = readLine
  var sum = 0
  var check = 0
  if(a>0){
    for(i <- 0 to get.size - 1){
      if(get(i) == '#') {
        check = 1
      } else if (check == 1 && get(i) == '.'){
        sum = sum + 1
      } else {
        check = 0
      }
    }
  }
  println(sum)
}