# encoding: utf-8
import random, sys
import time
inputs = lambda: map(int, raw_input().split())
debug = sys.stderr.write
random.seed()
h, w, k, t = inputs()
X, Y = h, w
Cars = [inputs() for i in xrange(k)]
Coms = []
com_str = "LRUD-"
dd = [(0, -1), (0, 1), (-1, 0), (1, 0), (0, 0)]
order = range(k)
ds = range(4)
def dist(x0, y0, x1, y1):
return abs(x0 - x1) + abs(y0 - y1)
# 整列
bucket = {}
ref = [0]*k
for i in xrange(k):
x0, y0, x1, y1 = Cars[i]
bucket.setdefault(y1, []).append(i)
ref[i] = len(bucket[y1])
lidx = {} # 左index
ridx = {} # 右index
count = {}
for key in bucket:
bucket[key].sort(key=lambda i: Cars[i][2])
lidx[key] = 0
ridx[key] = -1
count[key] = 0
# ランダムに散らしてみる
for _ in xrange(400):
random.shuffle(order)
exist = {(x0, y0) for x0, y0, x1, y1 in Cars}
coms = ["-"]*k
for i in order:
random.shuffle(ds)
wild = random.randint(0, 3)
x0, y0, x1, y1 = Cars[i]
for d in ds:
dx, dy = dd[d]
nx = x0 + dx; ny = y0 + dy
if not 0 < nx <= X or not 0 < ny <= Y:
continue
if not wild and dist(x0, y0, x1, y1) <= dist(nx, ny, x1, y1):
continue
if (nx, ny) not in exist:
exist.add((nx, ny))
Cars[i] = (nx, ny, x1, y1)
coms[i] = com_str[d]
break
Coms.append("".join(coms))
# まず整列
ready = set()
while len(ready) < k and len(Coms) < 2000:
random.shuffle(order)
exist = {(x0, y0) for x0, y0, x1, y1 in Cars}
coms = ["-"]*k
lmi = min(lidx[key] for key in lidx if count[key] < len(bucket[key]))
rmi = max(ridx[key] for key in ridx if count[key] < len(bucket[key]))
for i in order:
if i in ready:
continue
x0, y0, x1, y1 = Cars[i]
lst = bucket[y1]
g = None
if lst[lidx[y1]] == i:
g = (lidx[y1], y1)
elif lst[ridx[y1]] == i:
g = (X+ridx[y1], y1)
random.shuffle(ds)
if g is None:
wild = random.randint(0, 5)
else:
wild = random.randint(0, 1)
if len(ready) > k-10:
wild = random.randint(0, 2) < 1
xx = X/2 - len(lst)/2 + ref[i]
yy = y1
for d in ds:
dx, dy = dd[d]
nx = x0 + dx; ny = y0 + dy
if not 0 < nx <= X or not 0 < ny <= Y:
continue
if not wild:
if g is not None:
if dist(x0, y0, g[0]+1, g[1]) <= dist(nx, ny, g[0]+1, g[1]):
continue
else:
if dist(x0, y0, xx, yy) <= dist(nx, ny, xx, yy):
continue
if g is None:
if nx-1 < lidx[ny] + 3 and d == 2:
continue
if X + ridx[ny] - 3 < nx-1 and d == 3:
continue
else:
if not g[1] - 2 < ny < g[1] + 2:
if nx-1 < lidx[ny] + 4 and d == 2:
continue
if X + ridx[ny] - 4 < nx-1 and d == 3:
continue
else:
if nx-1 < lidx[y1] and d == 2:
continue
if X + ridx[ny] < nx-1 and d == 3:
continue
if (nx, ny) not in exist:
exist.add((nx, ny))
Cars[i] = (nx, ny, x1, y1)
coms[i] = com_str[d]
if g is not None and nx == g[0]+1 and ny == g[1]:
if not lmi+1 < nx-1 < X+rmi-1:
ready.add(i)
if lst[lidx[y1]] == i:
if lidx[y1] < len(lst)/2:
lidx[y1] += 1
count[y1] += 1
else:
if len(lst)+ridx[y1] > len(lst)/2+1:
ridx[y1] -= 1
count[y1] += 1
break
Coms.append("".join(coms))
# 最後に進んで配置
update = 1
while update:
update = 0
exist = {(x0, y0) for x0, y0, x1, y1 in Cars}
coms = ["-"]*k
for i in xrange(k):
x0, y0, x1, y1 = Cars[i]
if x0 < x1:
nx = x0 + 1
if (nx, y0) not in exist:
Cars[i] = (nx, y0, x1, y1)
coms[i] = "D"
exist.add((nx, y0))
update = 1
elif x1 < x0:
nx = x0 - 1
if (nx, y0) not in exist:
Cars[i] = (nx, y0, x1, y1)
coms[i] = "U"
exist.add((nx, y0))
update = 1
Coms.append("".join(coms))
sys.stdout.write("%d\n" % len(Coms))
sys.stdout.write("\n".join(Coms))