#include 
     
      #include 
      
       #include 
       
        #include 
        
         using namespace std;const int MAXN = 101;typedef struct {    int c[3];    int cnt;}state;queue
         
           q;int s[3];bool vis[MAXN][MAXN][MAXN];int dir[6][2] = { {
   0,1}, {
   1,0},                  {
    0,2}, {
   2,0},                  {
    1,2}, {
   2,1}                };bool ok(state x){    if ( x.c[0] == x.c[1] && x.c[0] * 2 == s[0] )        return true;    if ( x.c[1] == x.c[2] && x.c[1] * 2 == s[0] )        return true;    if ( x.c[0] == x.c[2] && x.c[0] * 2 == s[0] )        return true;    return false;}void pour(state& x, int from, int to){    if ( x.c[from] > 0 )    {        int amount = min(x.c[from], s[to] - x.c[to]);        x.c[from] -= amount;        x.c[to] += amount;        x.cnt++;    }}int BFS(){    if ( s[0] & 1 == 1 )        return -1;    while ( !q.empty() )        q.pop();    state first;    first.c[0] = s[0];    first.c[1] = 0;    first.c[2] = 0;    first.cnt = 0;    vis[first.c[0]][first.c[1]][first.c[2]] = true;    q.push(first);    while ( !q.empty() )    {        state curr = q.front();        q.pop();        if ( ok(curr) )            return curr.cnt;        for (int i = 0; i < 6; i++)        {            state next = curr;            pour(next, dir[i][0], dir[i][1]);            if ( !vis[next.c[0]][next.c[1]][next.c[2]] )            {                vis[next.c[0]][next.c[1]][next.c[2]] = true;                q.push(next);            }        }    }    return -1;}int main(){//    freopen("1.txt","r",stdin);    while ( scanf("%d%d%d", &s[0], &s[1], &s[2]) == 3 )    {        if ( s[0] == 0 && s[1] == 0 && s[2] == 0 )            break;        memset(vis, 0, sizeof(vis));        int ans = BFS();        if ( ans == -1 )            printf("NO\n");        else            printf("%d\n",ans);    }    return 0;}