#include<iostream>
#include<cctype>
#include<cstdio>
#include<cstring>
using namespace std;
char String[110];
int Count,Length;
int main()
{
while(scanf("%s",String) != EOF)
{
Count = 0;
Length = strlen(String);
for(int i = 1; i < Length; i++)
if(isupper(String[i]))
++Count;
if(isupper(String[0]) && (Count == (Length - 1)))
{
for(int i = 0; i < Length; i++)
String[i] = tolower(String[i]);
}
else
{
if(islower(String[0]) && (Count == (Length - 1)))
{
String[0] = toupper(String[0]);
for(int i = 1; i < Length; i++)
String[i] = tolower(String[i]);
}
}
for(int i = 0; i < Length; i++)
printf("%c",String[i]);
printf("\n");
//printf("%d %d\n",Count,Length);
}
return 0;
}