1 //#####################
 2 //Author:fraud
 3 //Blog: http://www.cnblogs.com/fraud/
 4 //#####################
 5 #include <iostream>
 6 #include <sstream>
 7 #include <ios>
 8 #include <iomanip>
 9 #include <functional>
10 #include <algorithm>
11 #include <vector>
12 #include <string>
13 #include <list>
14 #include <queue>
15 #include <deque>
16 #include <stack>
17 #include <set>
18 #include <map>
19 #include <cstdio>
20 #include <cstdlib>
21 #include <cmath>
22 #include <cstring>
23 #include <climits>
24 #include <cctype>
25 using namespace std;
26 #define XINF INT_MAX
27 #define INF 0x3FFFFFFF
28 #define MP(X,Y) make_pair(X,Y)
29 #define PB(X) push_back(X)
30 #define REP(X,N) for(int X=0;X<N;X++)
31 #define REP2(X,L,R) for(int X=L;X<=R;X++)
32 #define DEP(X,R,L) for(int X=R;X>=L;X--)
33 #define CLR(A,X) memset(A,X,sizeof(A))
34 #define IT iterator
35 typedef long long ll;
36 typedef pair<int,int> PII;
37 typedef vector<PII> VII;
38 typedef vector<int> VI;
39 int vis[1010];
40 int num[1010];
41 int main()
42 {
43     ios::sync_with_stdio(false);
44     string s;
45     while(cin>>s){
46         int len=s.length();
47         CLR(vis,0);
48         CLR(num,0);
49         int ans=1;
50         int cs=0;
51         int k=len/3;
52         if(k*3!=len)ans=0;if(ans){
53         char str=s[0];
54         for(int i=0;i<k;i++){
55             if(s[i]!=str)ans=0;
56         }
57         str=s[k];
58         if(s[k]==s[k-1])ans=0;
59         for(int i=k;i<len-k;i++){
60             if(s[i]!=str)ans=0;
61         }
62         str=s[len-k];
63         if(str==s[len-k-1])ans=0;
64         if(str==s[0])ans=0;
65         for(int i=len-k;i<len;i++){
66             if(s[i]!=str)ans=0;
67         }
68         }
69         if(ans)cout<<"YES"<<endl;
70         else cout<<"NO"<<endl;
71     }
72             
73     return 0;
74 }