#define _CRT_SECURE_NO_WARNINGS
#pragma comment(linker, "/stack:16777216")
#include <string>
#include <vector>
#include <map>
#include <list>
#include <iterator>
#include <set>
#include <queue>
#include <iostream>
#include <sstream>
#include <stack>
#include <deque>
#include <cmath>
#include <memory.h>
#include <cstdlib>
#include <cstdio>
#include <cctype>
#include <algorithm>
#include <utility>
#include <time.h>
using namespace std;

#define FOR(i, a, b) for(int i = (a); i < (b); ++i)
#define RFOR(i, b, a) for(int i = (b) - 1; i >= (a); --i)
#define REP(i, N) FOR(i, 0, N)
#define RREP(i, N) RFOR(i, N, 0)
#define FILL(A,value) memset(A,value,sizeof(A))

#define ALL(V) V.begin(), V.end()
#define SZ(V) (int)V.size()
#define PB push_back
#define MP make_pair
#define Pi 3.14159265358979

typedef long long Int;
typedef unsigned long long UINT;
typedef vector <int> VI;
typedef pair <int, int> PII;

const int INF = 1000000000;
const int MAX = 1024;
const int MAX2 = 7000;
const int BASE = 1000000000;

int n;
char A[MAX][MAX];
int dx[] = {0, -1, 0, 1};
int dy[] = {1, 0, -1, 0};
string str[] = {"R", "U", "L", "D"};
int x, y;
string res;
bool B[MAX*MAX];

bool OK(int x, int y)
{
    return (x >= 0 && y >= 0 && x < n && y < n);
}

// This method will process cnt operations from cyclic string t
void Run(string t, int cnt)
{
    FOR (j,0,cnt)
    {
        res += t[j % SZ(t)];
        x = x + dx[t[j % SZ(t)] - '0'];
        y = y + dy[t[j % SZ(t)] - '0'];
    }
}

int main()
{
    int T;
    scanf("%d", &T);
    FOR (test,0,T)
    {
        scanf("%d", &n);
        FOR (i,0,n)
            scanf("%s", A[i]);
        // Lets at first forget about any forbidden cells and travel the N*N board
        // from (1, 1) with no two consecutive operations that are the same
        
        // Some operations sequences
        // Go to the left
        string l = "3010";
        // Go to the right
        string r = "3212";
        // Go down from the left side
        string dl = "032";
        // Go down from the right sode
        string dr = "230";
        // Go left in the last row (if N%2 = 1)
        string ll = "103";
        // Go right in the last row (if N%2 = 1)
        string rr = "123";
        res = "";
        x = 0, y = 0;
        for (int i = 0; i < n; i += 2)
        {
            string t;
            if ((i/2) % 2 == 0)
            {
                if (i == n-1)
                    Run(ll, 3*(n-1));
                else
                {
                    Run(l, 2*n-1);
                    if (i+2 != n)
                        Run(dr, x == i ? 6 : 3);
                }
            }
            else
            {
                if (i == n-1)
                    Run(rr, 3*(n-1));
                else
                {
                    Run(r, 2*n-1);
                    if (i+2 != n)
                        Run(dl, x == i ? 6 : 3);
                }
            }
        }
        
        // Now what can you simply do is when you hit any forbidden cell, swap the move that caused it with the next one
        // After that it can be proven that no more than 3 consecutive operations will be the same
        FILL(B, 0);
        int pos = 0;
        x = 0, y = 0;
        while (pos < SZ(res))
        {
            if (A[x][y] != '.')
            int xx = x + dx[res[pos] - '0'];
            int yy = y + dy[res[pos] - '0'];
            if (A[xx][yy] == '#')
            {
                if (pos == SZ(res)-1)
                {
                    B[pos] = 1;
                    break;
                }
                if (((res[pos]-'0')+2) % 4 == (res[pos+1]-'0'))
                {
                    B[pos] = B[pos+1] = 1;
                    pos += 2;
                }
                else
                    swap(res[pos], res[pos+1]);
            }
            else
            {
                x = xx;
                y = yy;
                ++ pos;
            }
        }
        // Output the result
        string ans = "";
        FOR (i,0,SZ(res))
            if (B[i] == 0)
                ans += str[res[i] - '0'];
        printf("%s\n", ans.c_str());

    }
    return 0;
}