#include<stdio.h>
int main(void)
{
char ch;
printf("Input ch:");
scanf("%c",&ch);
if ((ch>='A')&&(ch<='Z'))
{ ch=getchar();
ch=ch+32;
printf("%c\n",ch);
}
else if ((ch>='a')&&(ch<='z'))
{ ch=getchar();
ch=ch-32;
printf("%c\n",ch);
}
return 0;
}