#include<iostream>
#include<conio.h>
#include<string>
using namespace std;
char unCAPS(int state, char symbel)
{
    char out_symb;
    if (((int)symbel >= 65 && (int)symbel <= 90) && state ==0)
    {
        out_symb = (char)(symbel + 32);
        return out_symb;
    }

    if (((int)symbel >= 97 && (int)symbel <=122 ) && state == 1)
    {
        out_symb = (char)(symbel - 32);
        return out_symb;
    }

    return symbel;
}

int main()
{
    char str[10000] = { NULL }, str2[10000] = { NULL };
    int state = 1;
    cin.get(str, 10000);
    for (size_t i = 0; i < strlen(str); i++)
    {
        str2[i] = unCAPS(state, str[i]);
        if ((int)str[i] != 32)
        {
            state = 0;
        }
        if ((int)str[i] == 46 || (int)str[i] == 33 || (int)str[i] == 63)
        {
            state = 1;
        }

    }
    for (size_t i = 0; i < strlen(str2); i++)
    {
        cout << str2[i];
    }

    return 0;
}