#include<iostream>
using namespace std;

char* str_invert(char *s)
{
	s = s - 32;
	s = s + 32;

	return s;
}

int main()
{
	char ch;
	char b;
	cout << "Introdu litere mari: ";
	cin >> ch;
	cout << "Introdu litere mici:";
	cin >> ch;
	b = str_invert(ch);
	cout << b << endl;
	return 0;
}