#include <bits/stdc++.h>
using namespace std;
int main()
{
string a;
cin.tie(0);
cout.tie(0);
while(cin>>a)
{
for(int i=0;i<a.size();i++)
{
if(a[i]>='A'&&a[i]<='Z')
a[i]=a[i]+32;
else if(a[i]>='a'&&a[i]<='z')
a[i]=a[i]-32;
else a[i]=a[i];
}
cout<<a<<endl;
}
return 0;
}