Problem:
Toggling Cases

Write a program which converts uppercase/lowercase letters to lowercase/uppercase for a given string.

Input

A string is given in a line.

Output

Print the converted string in a line. Note that you do not need to convert any characters other than alphabetical letters.

Constraints

The length of the input string < 1200

Sample Input

fAIR, LATER, OCCASIONALLY CLOUDY.

Sample Output

Fair, later, occasionally cloudy.

Solution in C (judge verdict: Time Limit Exceeded)

#include <stdio.h>
#include <ctype.h>
int main(void)
{
	char c;
	while(scanf("%c", &c), c != '\0'){
	    if(isalpha(c)){
			if(isupper(c)){
				printf("%c", tolower(c));
			}else{
				printf("%c", toupper(c));
			}
		}else{
				printf("%c", c);
		}
	}
	puts("");
    return 0;
}