import strutils
 
let read* = iterator: string =
  while true: (for s in stdin.readLine.split: yield s)
 
template input*(T: static[typedesc]): untyped = 
  when T is int: read().parseInt
  elif T is float: read().parseFloat
  elif T is string: read()
  elif T is char: read()[0]

let N = input(int)
let S = "#" & input(string)
var res = 0
for i in 1 .. N:
  if S[i] == 'M':
    for j in 1 .. N:
      if 1 <= i - j and i + j <= N:
        if S[i - j] == 'U' and S[i + j] == 'G':
          inc res
      else:
        break
echo res