1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 using namespace std;
 5 const int N = 21;
 6 int dp[N][N][N];
 7 
 8 void init()
 9 {
10     memset(dp,-1,sizeof(dp));
11     for(int i = 0; i <= 21; i++)
12     {
13         for(int j = 0; j <=21; j++)
14         {
15             dp[0][i][j] = dp[i][j][0] = dp[i][0][j] = 1;
16         }
17     }
18 }
19 int w(int a, int b, int c)
20 {
21     if(dp[a][b][c]!=-1) return dp[a][b][c];
22     if(a<b&&b<c){
23         return dp[a][b][c] = w(a,b,c-1)+w(a,b-1,c-1)-w(a,b-1,c);
24     }
25     else return dp[a][b][c] = w(a-1, b, c) + w(a-1, b-1, c) + w(a-1, b, c-1) - w(a-1, b-1, c-1);
26 }
27 int main()
28 {
29     init();
30     int a, b, c;
31     while(~scanf("%d%d%d",&a,&b,&c))
32     {
33         //printf("w = %d\n",w(20,20,20));
34         if(a==-1&&b==-1&&c==-1) return 0;
35         else if(a<=0||b<=0||c<=0) printf("w(%d, %d, %d) = 1\n",a,b,c);
36         else if(a>20||b>20||c>20) printf("w(%d, %d, %d) = %d\n",a,b,c,w(20,20,20));
37         else printf("w(%d, %d, %d) = %d\n",a,b,c,w(a,b,c));
38     }
39     return 0;
40 }