C :

#include "stdio.h"
int m,n,x,y;
long long f[21][21];
int dx[]={1,1,-1,-1,2,2,-2,-2};
int dy[]={2,-2,2,-2,1,-1,1,-1};
int Exit(int x,int y){return x>=0&&x<=n&&y>=0&&y<=m;}
int main()
{
	int i,j;
	scanf("%d%d%d%d",&n,&m,&x,&y);
	f[0][0]=1;
	f[x][y]=-1;
	for(i=0;i<8;i++)
	{
		if(Exit(x+dx[i],y+dy[i]))
			f[x+dx[i]][y+dy[i]]=-1;
	}
	for(i=0;i<=n;i++)
	{
		for(j=0;j<=m;j++)
		{
			if(f[i][j]==-1)
			{
				f[i][j]=0;
				continue;
			}
			if(Exit(i-1,j))
				f[i][j]+=f[i-1][j];
			if(Exit(i,j-1))
				f[i][j]+=f[i][j-1];
		}
	}
	printf("%lld\n",f[n][m]);
	return 0;
}

C++ :

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int n,m,x,y;
int dx[8]={-1,-2,-2,-1,1,2,2,1},
	dy[8]={-2,-1,1,2,2,1,-1,-2};
long long f[25][25]={0};
bool flag[25][25]={0};
int main()
{
	//freopen("pawn.in","r",stdin);
	//freopen("pawn.out","w",stdout);
	memset(flag,0,sizeof(flag));
	memset(f,0,sizeof(f));
	cin>>n>>m>>x>>y;
	flag[x][y]=1;
	for(int i=0;i<8;i++)
	{
		int d_x=dx[i]+x,d_y=dy[i]+y;
		if(d_x>=0&&d_x<=n&&d_y>=0&&d_y<=m)
		{
			//cout<<d_x<<' '<<d_y<<endl;
			flag[d_x][d_y]=1;
		}
	}
	for(int i=0;i<=m;i++)
	{
		if(flag[0][i])break;
		f[0][i]=1;		
	}	
	for(int i=0;i<=n;i++)
	{
		if(flag[i][0])break;
		f[i][0]=1;
	}
	for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++)
		{
			if(flag[i][j])
			{
				f[i][j]=0;				
			}else
			f[i][j]=f[i-1][j]+f[i][j-1];
			//cout<<i<<' '<<j<<' '<<f[i][j]<<endl;
		}
	cout<<f[n][m]<<endl;
	return 0;
}

Pascal :

var a:array[-2..22,-2..22]of int64;
    m,n,x,y,i,j:integer;
begin
  readln(n,m,x,y);
  a[0,0]:=1;
  a[x,y]:=-1;
  a[x-1,y-2]:=-1;
  a[x-2,y-1]:=-1;
  a[x-1,y+2]:=-1;
  a[x-2,y+1]:=-1;
  a[x+1,y+2]:=-1;
  a[x+2,y+1]:=-1;
  a[x+1,y-2]:=-1;
  a[x+2,y-1]:=-1;
  for i:=0 to n do
   for j:=0 to m do
    if a[i,j]>=0 then
     begin
      if a[i-1,j]>0 then a[i,j]:=a[i,j]+a[i-1,j];
      if a[i,j-1]>0 then a[i,j]:=a[i,j]+a[i,j-1];
     end;
  writeln(a[n,m]);
end.