1 #include <iostream> 2 #include <queue> 3 #include <cstdio> 4 #include <cstring> 5 using namespace std; 6  7 #define MAXN 105 8  9 bool visit[MAXN][MAXN][MAXN];10 11 typedef struct node_t {12     int x[3];13     int t;14     node_t() {}15     node_t(int xx, int yy, int ss, int tt) {16         x[0] = xx;17         x[1] = yy;18         x[2] = ss;19         t = tt;20     }21 } node_t;22 23 int s, m, n;24 25 bool check(node_t d) {26     int half = s>>1;27 28     if ((d.x[0]==half) && (d.x[1]==0 || d.x[2]==0)) return true;29     if ((d.x[0]==0) && (d.x[1]==half)) return true;30 31     return false;32 }33 34 int bfs() {35     if (s & 1)36         return -1;37     queue<node_t> Q;38     int x[3] = {m, n, s};39     int i, j, k, tmp;40 41     memset(visit, false, sizeof(visit));42     visit[0][0][s] = true;43     Q.push(node_t(0,0,s,0));44 45     while (!Q.empty()) {46         node_t d = Q.front();47         Q.pop();48         for (i=0; i<3; ++i) {49             for (j=0; j<3; ++j) {50                 if (i == j)51                     continue;52                 node_t dd = d;53                 // from i to j54                 tmp = x[j] - dd.x[j];55                 if (tmp > 0) {56                     if (dd.x[i] > tmp) {57                         dd.x[j] = x[j];58                         dd.x[i] -= tmp;59                     } else {60                         dd.x[j] += dd.x[i];61                         dd.x[i] = 0;62                     }63                 }64                 if (visit[dd.x[0]][dd.x[1]][dd.x[2]]) {65                     continue;66                 }67                 ++dd.t;68                 visit[dd.x[0]][dd.x[1]][dd.x[2]] = true;69                 if ( check(dd) )70                     return dd.t;71                 Q.push(dd);72             }73         }74     }75 76     return -1;77 }78 79 int main() {80 81 #ifndef ONLINE_JUDGE82     freopen("data.in", "r", stdin);83 #endif84 85     while (scanf("%d%d%d",&s,&m,&n)!=EOF && (s||m||n)) {86         int ans = bfs();87         if (ans > 0)88             printf("%d\n", ans);89         else90             printf("NO\n");91     }92 93     return 0;94 }