#include<iostream>
using namespace std;
int main()
{
    string S;
    cin >> S;
    for(int i = 0; i < S.size(); i++)
    {
        if(isupper(S[i]))
        {
            S[i] = tolower(S[i]);
        }
        else if(islower(S[i]))
        {
            S[i] = toupper(S[i]);
        }
    }
    cout << S << endl;
    return 0;
}