题解

#include<iostream>
#include<string>
using namespace std;
int main(){
    string s,s1,s2;
    cin>>s;
    for(int i=0;i<s.size();i++){
        if(i%2==0){
            s1+=s[i];
        }else{
            s2+=s[i];
        }
    }
    if(s1>s2){
        cout<<s1<<s2;
    }else{
        cout<<s2<<s1;
    }
    return 0;
}