> #include<iostream>
> using namespace std;
> 
> int main()
> {
> 	int w[21][21][21];
> 	int a,b,c;
> 	int i,j,k;
> 	for(i=0;i<=20;i++)
> 	{
> 		for(j=0;j<=20;j++)
> 		{
> 			w[0][i][j]=1;
> 			w[i][0][j]=1;
> 			w[i][j][0]=1;
> 		}
> 	}
> 	while(cin>>a>>b>>c)
> 	{
> 		if(a==-1 && b==-1 && c==-1)
> 			return 0;
> 		if(a<0 || b<0 || c<=0)
> 		{
> 			cout<<"w("<<a<<", "<<b<<", "<<c<<") = "<<1<<endl;
> 			continue;
> 		}
> 		if(a>20 || b>20 || c>20)
> 		{
> 			a=b=c=20;
> 		}
> 		for(i=1;i<=a;i++)
> 		{
> 			for(j=1;j<=b;j++)
> 			{
> 				for(k=1;k<=c;k++)
> 				{
> 					if(i<j && j<k)
> 						w[i][j][k]=w[i][j][k-1]+w[i][j-1][k-1]-w[i][j-1][k];
> 					else
> 						w[i][j][k]=w[i-1][j][k]+w[i-1][j-1][k]+w[i-1][j][k-1]-w[i-1][j-1][k-1];
> 				}
> 			}
> 		}
> 		cout<<"w("<<a<<", "<<b<<", "<<c<<") = "<<w[a][b][c]<<endl;
> 		for(i=1;i<=a;i++)
> 		{
> 			for(j=1;j<=b;j++)
> 			{
> 				for(k=1;k<=c;k++)
> 					w[i][j][k]=0;
> 			}
> 		}
> 	}
> 	return 0;
> }