include <bits/stdc++.h>

using namespace std;

int main()
{
string s;
getline(cin, s);
for(int i = 1; i < s.length(); i++)
while(s[i-1] == ' ' && s[i] == ' ') s.erase(i, 1);
if(s[0] == ' ') s.erase(0,1);
if(s[s.length()-1] == ' ') s.erase(s.length()-1, 1);
cout << s;
return 0;
}

include <bits/stdc++.h>

using namespace std;

int main()
{
string s;
getline(cin, s);
for(int i = 0; i < s.length(); i++){
if(islower(s[i])) s[i] = toupper(s[i]);
else if(isupper(s[i])) s[i] = tolower(s[i]);
}
cout << s;
return 0;
}

https://drive.google.com/drive/folders/1WpnWevB4VanXNeu96uxKINacr7cReLxz?usp=drive_link

https://docs.google.com/document/d/1Yen7Ixbem1dEpLe4wT7G82zbxfuE425I/edit?usp=sharing&ouid=117114481638232669181&rtpof=true&sd=true
```