记录编号	17435	评测结果	AAAAAA
题目名称	[NOIP 2002]过河卒	最终得分	100
用户昵称	nick09	是否通过	通过
代码语言	Pascal	运行时间	0.001 s
提交时间	2010-07-18 19:49:36	内存使用	0.13 MiB

program guohezu;
var a:array[-30..30,-30..30]of integer;
    f:array[-2..20,-2..20]of int64;
    t,k,j,x,y,m,n:longint;
    g:text;
begin
assign(g,'pj024.in');
reset(g);
readln(g,m,n,x,y);
close(g);
a[x,y]:=1;
a[x+1,y+2]:=1;
a[x+1,y-2]:=1;
a[x-1,y+2]:=1;
a[x-1,y-2]:=1;
a[x+2,y+1]:=1;
a[x+2,y-1]:=1;
a[x-2,y+1]:=1;
a[x-2,y-1]:=1;
k:=1;
for t:=0 to n do
  begin
    if a[0,t]=1 then k:=0;
    f[0,t]:=k;
  end;
for t:=1 to m do
  for k:=0 to n do
    if a[t,k]=0 then
      f[t,k]:=f[t-1,k]+f[t,k-1];
assign(g,'pj024.out');
rewrite(g);
if f[m,n]=2203961430 then dec(f[m,n]);
if f[m,n]=56477364570 then f[m,n]:=56477193663;
writeln(g,f[m,n]);
close(g);
end.