#include <stdio.h>
int main() {
char c;
do {
c=getchar
scanf("%c", &c);
if (c >= 'A' && c <= 'Z') {
int letter = c + 32;
printf("%c", letter);
} else if (c >= 'a' && c <= 'z') {
int letter = c - 32;
printf("%c", letter);
}
printf("%c", c);
}
}
while (c != '.')
;
return 0;
}