import math
a=int(raw_input())
l1=map(int,raw_input().strip().split())
x1=l1[0]
y1=l1[1]
x2=l1[2]
y2=l1[3]
w=y2-y1
l=[]
if (x1-x2)%2==1:
    print "Impossible"
elif ((math.fabs(x2-x1)/2)-math.fabs(y2-y1))%2==1:
    print "Impossible"
else:
    if x1-x2>0:
        if y2-y1>0:
            if ((x1-x2)/2)<=(y2-y1):
                l=l+["UR"]*((x1-x2)/2)
                l=l+["R"]*(((y2-y1)-(x1-x2)/2)/2)
            else:
                m=(((x1-x2)/2+(y2-y1))/2)
                n=((x1-x2)/2-(y2-y1))/2
                l=l+["UL"]*n
                l=l+["UR"]*m
        else:
            if ((x1-x2)/2)<=(y1-y2):
                l=l+["UL"]*(((x1-x2)/2))
                l=l+["L"]*(((y1-y2)-(x1-x2)/2)/2)
            else:
                m=((x1-x2)/2+(y1-y2))/2
                n=((x1-x2)/2-(y1-y2))/2
                l=l+["UL"]*(m)
                l=l+["UR"]*(n)
    else:
        if y2-y1>0:
            if ((x2-x1)/2)<=(y2-y1):
                l=l+["R"]*(((y2-y1)-((x2-x1)/2))/2)
                l=l+["LR"]*((x2-x1)/2)
            else:
                m=(((x2-x1)/2+(y2-y1))/2)
                n=(((x2-x1)/2-(y2-y1))/2)
                l=l+["LR"]*(m)
                l=l+["LL"]*(n)
        else:
            if ((x2-x1)/2)<=(y1-y2):
                l=l+["LL"]*((x2-x1)/2)
                l=l+["L"]*(((y1-y2)-(x2-x1)/2)/2)
            else:
                m=(((x2-x1)/2+(y1-y2))/2)
                n=((x2-x1)/2-(y1-y2))/2
                l=l+["LR"]*(n)
                l=l+["LL"]*(m)
    print len(l)
    for u in l:
        print u,
    print