ac

#include<iostream>
#include<cstring>
using namespace std;
int main(){
char a[10001];
cin>>a;
for(int i=0;i<strlen(a);i++){
if(a[i]>='A' &&a[i]<='Z'){
a[i]+=32;
}
else if(a[i]>='a' &&a[i]<='z'){
a[i]-=32;
}
}
cout<<a;
return 0;
}