#include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
using namespace std;
int main(){
    string str;
    cin >> str;
    for(int i=0;i<str.size();i++){
        if(str[i]>='a'&&str[i]<='z') str[i]+=32;
        else if(str[i]>='A'&&str[i]<='Z') str[i]-=32; 
    }
    cout << str;
    return 0;
}