Div 2 Problem I

#include<cstdio>
#include<cstring>
#include<string>
#include<cmath>
#include<iostream>
#include<cctype>
#include<map>
#include<stack>
#include<cstdlib>
#include <queue>
#include <vector>
#include<algorithm>
#define ll long long
#define sc scanf
#define pf printf
#define Pi 2*acos(0.0)
using namespace std;
int main()
{
    char s[21];
    while(sc("%s",s)==1)
    {
        if(s[0]>='A'&&s[0]<='Z')
        {
            pf("%s\n",strlwr(s));
        }
        else
        pf("%s\n",strupr(s));
    }
    return 0;
}