CF 2155B

package main

import "fmt"

func main() {
    var t int
    fmt.Scan(&t)
    for i := 0; i < t; i++ {
        var n, kf int
        fmt.Scan(&n, &kf)
        if n*n-kf == 1 {
            fmt.Println("NO")
            continue
        }
        fmt.Println("YES")
        count := 0
        for j := 0; j < n; j++ {
            control := false
            for k := 0; k < n; k++ {
                count++
                if count <= kf {
                    fmt.Print("L")
                    continue
                }
                if k == n-1 && j != n-1 {
                    fmt.Print("D")
                    continue
                }
                if !control {
                    control = !control
                    fmt.Print("R")
                    continue
                } else {
                    fmt.Print("L")
                    continue
                }
            }
            fmt.Println()
        }
    }
}