1 #include <cstdio>
 2 #include <queue>
 3 using namespace std;
 4
 5 bool mar[101][101][101];
 6 int S, N, M;
 7 struct Sta {
 8     int a, b, c, t;
 9     void init(int x, int y, int z, int cost) {
10         a = x;
11         b = y;
12         c = z;
13         t = cost;
14     }
15     void mark() {
16         mar[a][b][c] = true;
17     }
18 };
19 Sta tt, st;
20 queue<Sta> Q;
21 bool AtoB(int a, int &sa, int b, int &sb) {
22     if (b - sb >= sa) {
23         sb += sa;
24         sa = 0;
25     } else {
26         sa -= b - sb;
27         sb = b;
28     }
29     if ((tt.a == S / 2 && tt.b == S / 2) || (tt.a == S / 2 && tt.c == S / 2) || (tt.b == S / 2 && tt.c == S / 2))
30         return true;
31     else {
32         if (!mar[tt.a][tt.b][tt.c]) {
33             tt.t++;
34             tt.mark();
35             Q.push(tt);
36         }
37     }
38     return false;
39 }
40
41 int bfs() {
42     while (!Q.empty()) {
43         st = Q.front();
44         Q.pop();
45         tt = st;
46         if (AtoB(S, tt.a, N, tt.b))
47             return tt.t + 1;
48         tt = st;
49         if (AtoB(S, tt.a, M, tt.c))
50             return tt.t + 1;
51         tt = st;
52         if (AtoB(N, tt.b, S, tt.a))
53             return tt.t + 1;
54         tt = st;
55         if (AtoB(N, tt.b, M, tt.c))
56             return tt.t + 1;
57         tt = st;
58         if (AtoB(M, tt.c, S, tt.a))
59             return tt.t + 1;
60         tt = st;
61         if (AtoB(M, tt.c, N, tt.b))
62             return tt.t + 1;
63     }
64     return -1;
65 }
66
67 int main() {
68     while (~scanf("%d%d%d", &S, &N, &M) && !(S == 0 && N == 0 && M == 0)) {
69         if (S % 2 == 1) {
70             printf("NO\n");
71             continue;
72         }
73         for (int i = 0; i <= S; i++)
74             for (int j = 0; j <= S; j++)
75                 for (int k = 0; k <= S; k++)
76                     mar[i][j][k] = false;
77         while (!Q.empty())
78             Q.pop();
79         tt.init(S, 0, 0, 0);
80         tt.mark();
81         Q.push(tt);
82         int time = bfs();
83         if (time == -1)
84             printf("NO\n");
85         else
86             printf("%d\n", time);
87     }
88     return 0;
89 }