import java.io.*; import java.util.*; public class Main { static long MOD = 2 << 29; public static void main(String[] args) { FastScanner sc = new FastScanner(); int H = sc.nextInt(); int W = sc.nextInt(); int sy = sc.nextInt()-1; int sx = sc.nextInt()-1; int gy = sc.nextInt()-1; int gx = sc.nextInt()-1; char[][] map = new char[H][]; for(int i = 0; i < H; i++) { map[i] = sc.next().toCharArray(); } boolean[][] cap = new boolean[H][W]; int[] vx = {0,1,0,-1}; int[] vy = {1,0,-1,0}; ArrayDeque q = new ArrayDeque(); q.add(new Data(sx,sy)); while(!q.isEmpty()) { Data p = q.poll(); if(cap[p.y][p.x]) continue; cap[p.y][p.x] = true; for(int i = 0; i < 4; i++) { int tx = vx[i] + p.x; int ty = vy[i] + p.y; if(!rcheck(tx,ty,W,H)) continue; if(Math.abs(map[ty][tx] - map[p.y][p.x]) > 1) continue; if(cap[ty][tx]) continue; q.add(new Data(tx,ty)); } for(int i = 0; i < 4; i++) { int tx = vx[i]*2 + p.x; int ty = vy[i]*2 + p.y; if(!rcheck(tx,ty,W,H)) continue; if(Math.abs(map[ty][tx] - map[p.y][p.x]) != 0) continue; if(cap[ty][tx]) continue; q.add(new Data(tx,ty)); } } if(cap[gy][gx]) System.out.println("YES"); else System.out.println("NO"); } static boolean rcheck(int x, int y, int W, int H) { if(x < 0 || y < 0 || x >= W || y >= H) return false; return true; } static class Data { int x; int y; Data(int a, int b) { x = a; y = b; } } } class FastScanner { private final InputStream in = System.in; private final byte[] buffer = new byte[1024]; private int ptr = 0; private int buflen = 0; private boolean hasNextByte() { if (ptr < buflen) { return true; }else{ ptr = 0; try { buflen = in.read(buffer); } catch (IOException e) { e.printStackTrace(); } if (buflen <= 0) { return false; } } return true; } private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;} private boolean isPrintableChar(int c) { return 33 <= c && c <= 126;} private void skipUnprintable() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;} public boolean hasNext() { skipUnprintable(); return hasNextByte();} public String next() { if (!hasNext()) throw new NoSuchElementException(); StringBuilder sb = new StringBuilder(); int b = readByte(); while(isPrintableChar(b)) { sb.appendCodePoint(b); b = readByte(); } return sb.toString(); } public long nextLong() { if (!hasNext()) throw new NoSuchElementException(); long n = 0; boolean minus = false; int b = readByte(); if (b == '-') { minus = true; b = readByte(); } if (b < '0' || '9' < b) { throw new NumberFormatException(); } while(true){ if ('0' <= b && b <= '9') { n *= 10; n += b - '0'; }else if(b == -1 || !isPrintableChar(b)){ return minus ? -n : n; }else{ throw new NumberFormatException(); } b = readByte(); } } public int nextInt() { if (!hasNext()) throw new NoSuchElementException(); int n = 0; boolean minus = false; int b = readByte(); if (b == '-') { minus = true; b = readByte(); } if (b < '0' || '9' < b) { throw new NumberFormatException(); } while(true){ if ('0' <= b && b <= '9') { n *= 10; n += b - '0'; }else if(b == -1 || !isPrintableChar(b)){ return minus ? -n : n; }else{ throw new NumberFormatException(); } b = readByte(); } } }