import std.stdio;
import std.bigint;
import std.functional;
 
uint n = 100;
uint m = 100;	
uint x1 = 60;
uint y1 = 60;
uint k = 100;
 
alias memstep = memoize!(step, 100 * 100 * 200);
 
BigInt step(uint x, uint y, uint k){
 
	if (k==0) {
		return ((x==x1) && (y==y1)) ? BigInt("1") : BigInt("0");
	}
	else {
		auto up    = (y+1 < m) ? memstep(x, y+1, k-1) : BigInt("0");
		auto down  = (y-1 >= 0) ? memstep(x, y-1, k-1) : BigInt("0");
		auto left  = (x+1 < n) ? memstep(x+1, y, k-1) : BigInt("0");
		auto right = (x-1 >= 0) ? memstep(x-1, y, k-1) : BigInt("0");
 
		return up + down + left + right;
	}
}
 
void main()
{
	step(50, 50, 200).writeln;
}

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