rt，改了好几遍都WA QAQ

#include<bits/stdc++.h>
using namespace std;
long long f[25][25][25],a,b,c;
long long w(long long x,long long y,long long z){
	if(x<=0||y<=0||z<=0)
		return 1;
	else if(x>20||y>20||z>20)
		return w(20,20,20);
	else if(f[x][y][z]!=-1)
		return f[x][y][z];
	else if(x<y&&y<z)
		return f[x][y][z]=w(x,y,z-1)+w(x,y-1,z-1)-w(x,y-1,z);
	else 
		return f[x][y][z]=w(x-1,y,z)+w(x-1,y-1,z)+w(x-1,y,z-1)-w(x-1,y-1,z-1);
}
int main(){
	memset(f,-1,sizeof(f));
	while(scanf("%lld%lld%lld",&a,&b,&c)==3){	
		if(a==-1&&b==-1&&c==-1)break;
		cout<<"w("<<a<<','<<b<<','<<c<<") = ";
		if(a>20)a=21;
		if(b>20)b=21;
		if(c>20)c=21;
		//cout<<a<<" "<<b<<" "<<c<<" "<<endl;
		cout<<w(a,b,c)<<endl;
	}
	return 0;
}