题解

#include<iostream>
#include<cstring>
using namespace std;
int main(){
    char c[10010];
    cin>>c;
    for(int i=0;i<strlen(c);i++){
        if(c[i]>='a'&&c[i]<='z'){
            c[i]-=32;
        }else if(c[i]>='A'&&c[i]<='Z'){
            c[i]+=32;
        }
        cout<<c[i];
    }
    return 0;
}