#include <iostream>
#include <algorithm>

class alternating_case
{
  public:
    alternating_case();
    alternating_case(alternating_case const& f);

    alternating_case& operator =(alternating_case const& f);

    char operator ()(char c) const;

    void reset();

  private:
    enum STATE { UPPER, LOWER };
    mutable STATE state_;
};

alternating_case::alternating_case()
  : state_(UPPER)
{
}

alternating_case::alternating_case(alternating_case const& f)
  : state_(f.state_)
{
}

alternating_case& alternating_case::operator =(alternating_case const& f)
{
  state_ = f.state_;
  return *this;
}

char alternating_case::operator ()(char c) const
{
  if(state_ == UPPER)
  {
    state_ = LOWER;
    return std::toupper(c);
  }
  else if(state_ == LOWER)
  {
    state_ = UPPER;
    return std::tolower(c);
  }
}

void alternating_case::reset()
{
  state_ = UPPER;
}

int main()
{
  using namespace std;
  string line;
  while(getline(cin, line))
  {
    transform(line.begin(), line.end(), line.end(), alternating_case());
    cout << line << endl;
  }
}