A. cAPS lOCK

time limit per test
0.5 second
memory limit per test
256 megabytes
input
standard input
output
standard output

wHAT DO WE NEED cAPS LOCK FOR?
Caps lock is a computer keyboard key. Pressing it sets an input mode in which typed letters are capital by default. If it is pressed by accident, it leads to accidents like the one we had in the first passage.
Let’s consider that a word has been typed with the Caps lock key accidentally switched on, if:
either it only contains uppercase letters;
or all letters except for the first one are uppercase.

In this case we should automatically change the case of all letters. For example, the case of the letters that form words “hELLO”, “HTTP”, “z” should be changed.

Write a program that applies the rule mentioned above. If the rule cannot be applied, the program should leave the word unchanged.

Input
The first line of the input data contains a word consisting of uppercase and lowercase Latin letters. The word’s length is from 1 to 100 characters, inclusive.

Output
Print the result of the given word’s processing.

Examples
Input
cAPS
Output
Caps

Input
Lock
Output
Lock

問題連結：CodeForces - 131A

問題簡述：解決CapsLK按錯的問題。

問題分析：當單詞全為大寫時，將所有字母變為小寫。當單詞第一個字母為小寫，後面字母全為大寫時，將第一個字母改為大寫，將之後的字母改為小寫。

程式說明：用count統計單詞中大寫字母的數量，並用if篩選出字母全為大寫和除第一個字母外全為大寫兩種情況並對每個字母進行大小寫轉換處理。

AC通過程式碼：

#include<stdio.h>
#include<string.h>

int main()
{
	char s[100];
	int i,count=0;
	scanf("%s",s);
	getchar();
	if(strlen(s)>100) return 0;
	for(i=0;i<strlen(s);i++)
	{
		if(s[i]>='A'&&s[i]<='Z')
			count++;
	}
	if(count==strlen(s)-1&&s[0]>='a'&&s[0]<='z'||count==strlen(s))
	{
		for(i=0;i<strlen(s);i++)
		{
			if(s[i]>='A'&&s[i]<='Z')
			{
				s[i]+=32;
			}else
			{
				s[i]-=32;
			}
		}
	}
	printf("%s\n",s);
	return 0;
}