人民的题解

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