#!/usr/bin/env python3
import sys, re, functools

print(int((lambda c:abs(c.real)+abs(c.imag))(functools.reduce(lambda t,s:(lambda p,d,r:(p+int(s[1:])*r*d,r*d))(t[0],t[1],{"R":-1j,"L":1j}[s[0]]),re.findall(r"[RL]\d+",sys.stdin.readline()),(0,1))[0])))