Codeforces Round #605 (Div. 3), problem: (B)

#include<bits/stdc++.h>
using namespace std;
#define sf scanf
#define pf printf
#define pb push_back
#define pii pair<int,int>
#define pob pop_back
#define all(a) a.begin(),a.end()
#define fio ios_base::sync_with_stdio(false); cin.tie(0);cout.tie(0);
#define i64 long long int
#define mem(x,y) memset(x,y,sizeof(x))
#define fill(arr,b) fill(arr, arr+sizeof(arr)/sizeof(arr[0]), b)

const double pi = acos(-1.0);
const int maxn = (i64)2e5+5;
//L  = 76 ,R  = 82 ,U  = 85 ,D  = 68

int main()
{
    //freopen("input.txt","r",stdin);
    int t,i;

    cin>>t;
    while(t--)
    {
        string s;
        cin>>s;
        int L=0,R=0,U=0,D=0;
        int sz = s.size();
        for(i = 0 ; i<sz ; i++)
        {
            if(s[i] == 'L') L++;
            else if(s[i] == 'R') R++;
            else if(s[i] == 'U') U++;
            else if(s[i] == 'D') D++;
        }
        if(L > R) L = R;
        else R = L;
        if(U>D) U = D;
        else D = U;

        if(D == 0 && L == 0 && R == 0 && U == 0)
        {
            cout<<"0"<<endl;
        }
        else if(L == 0 && U!=0)
        {
            cout<<"2"<<endl<<"UD"<<endl;
        }
        else if(U == 0 && L!=0)
        {
            cout<<"2"<<endl<<"LR"<<endl;
        }
        else
        {
            cout<<L+D+U+R<<endl;
            while(L--) cout<<"L";
            while(U--) cout<<"U";
            while(R--) cout<<"R";
            while(D--) cout<<"D";
            cout<<endl;
        }
        s.clear();
    }

return 0;
}