题解

//#include<iostream>
#include<cstdio>
//#include<algorithm>
//#include<cmath>
//#include<string.h>

using namespace std;

int main()
{
char n;
scanf("%c",&n);
if(n>='A'&&n<='Z')
printf("%c",char(n-'A'+'a'));
else
printf("%c",char(n-'a'+'A'));
return 0;
}