atcoder#ABC265C. [ABC265C] Belt Conveyor

[ABC265C] Belt Conveyor

Score : 300300 points

Problem Statement

We have a grid with HH horizontal rows and WW vertical columns. (i,j)(i, j) denotes the square at the ii-th row from the top and jj-th column from the left. (i,j)(i,j) has a character Gi,jG_{i,j} written on it. Gi,jG_{i,j} is U, D, L, or R.

You are initially at (1,1)(1,1). You repeat the following operation until you cannot make a move.

Let (i,j)(i,j) be the square you are currently at. If Gi,jG_{i,j} is U and i1i \neq 1, move to (i1,j)(i-1,j). If Gi,jG_{i,j} is D and iHi \neq H, move to (i+1,j)(i+1,j). If Gi,jG_{i,j} is L and j1j \neq 1, move to (i,j1)(i,j-1). If Gi,jG_{i,j} is R and jWj \neq W, move to (i,j+1)(i,j+1). Otherwise, you cannot make a move.

Print the square you end up at when you cannot make a move. If you indefinitely repeat moving, print -1 instead.

Constraints

  • 1H,W5001 \leq H, W \leq 500
  • Gi,jG_{i,j} is U, D, L, or R.
  • HH and WW are integers.

Input

Input is given from Standard Input in the following format:

HH WW

G1,1G1,2G1,WG_{1,1}G_{1,2}\dots G_{1,W}

G2,1G2,2G2,WG_{2,1}G_{2,2}\dots G_{2,W}

\vdots

GH,1GH,2GH,WG_{H,1}G_{H,2}\dots G_{H,W}

Output

If you end up at (i,j)(i, j), print it in the following format:

ii jj

If you indefinitely repeat moving, print -1.

2 3
RDU
LRU
1 3

You will move as (1,1)(1,2)(2,2)(2,3)(1,3)(1, 1) \to (1, 2) \to (2, 2) \to (2, 3) \to (1, 3), ending up here, so the answer is (1,3)(1, 3).

2 3
RRD
ULL
-1

You will indefinitely repeat moving as $(1, 1) \to (1, 2) \to (1, 3) \to (2, 3) \to (2, 2) \to (2, 1) \to (1, 1) \to (1, 2) \to \dots$, so -1 should be printed in this case.

9 44
RRDDDDRRRDDDRRRRRRDDDRDDDDRDDRDDDDDDRRDRRRRR
RRRDLRDRDLLLLRDRRLLLDDRDLLLRDDDLLLDRRLLLLLDD
DRDLRLDRDLRDRLDRLRDDLDDLRDRLDRLDDRLRRLRRRDRR
DDLRRDLDDLDDRLDDLDRDDRDDDDRLRRLRDDRRRLDRDRDD
RDLRRDLRDLLLLRRDLRDRRDRRRDLRDDLLLLDDDLLLLRDR
RDLLLLLRDLRDRLDDLDDRDRRDRLDRRRLDDDLDDDRDDLDR
RDLRRDLDDLRDRLRDLDDDLDDRLDRDRDLDRDLDDLRRDLRR
RDLDRRLDRLLLLDRDRLLLRDDLLLLLRDRLLLRRRRLLLDDR
RRRRDRDDRRRDDRDDDRRRDRDRDRDRRRRRRDDDRDDDDRRR
9 5