$3,4$ 点 $\color{red}{WA}$ ，求助，用的 $DP$

#include<bits/stdc++.h>
using namespace std;
long long ax,ay,bx,by; // a为B点,b为马
typedef pair<long long,long long> h;
map<h,long long>dp;
int main(){
	cin>>ax>>ay>>bx>>by;
	for(long long i=0;i<=ax;i++){
		for(long long j=0;j<=ay;j++){
			dp[{i,j}]=1;
		}
	}
	dp[{bx,by}]=0,dp[{bx-2,by+1}]=0,dp[{bx-2,by-1}]=0,dp[{bx+2,by-1}]=0,dp[{bx+2,by+1}]=0,dp[{bx+1,by-2}]=0,dp[{bx-1,by-2}]=0,dp[{bx+1,by+2}]=0,dp[{bx-1,by+2}]=0;
	for(long long i=1;i<=ax;i++){
		for(long long j=1;j<=ay;j++){
			if(dp[{i,j}]!=0) dp[{i,j}]=dp[{i-1,j}]+dp[{i,j-1}];
		}
	}
	cout<<dp[{ax,ay}];
	return 0;
}