#include <cstdio>
#include <cstring>
#include <stack>
#include <vector>
#include <algorithm>
#include <queue>

#define ll long long
int const N = 100005;
int const M = 205;
int const INF = 0x3f3f3f3f;
ll const mod = 1000000007;

using namespace std;

int l;
int flag;
char s[1500];

void ini()
{
    flag=1;
    l=strlen(s);
}

void solve()
{
    int i;
    if(l%3!=0){
        flag=0;return;
    }
    int te=l/3;
    for(i=1;i<l/3;i++){
        if(s[i]!=s[i-1]){
            flag=0;return;
        }
        if(s[i+l/3]!=s[i+l/3-1]){
            flag=0;return;
        }
        if(s[i+l/3*2]!=s[i+l/3*2-1]){
            flag=0;return;
        }
    }
    if(s[0]==s[l/3] || s[0]==s[l/3*2] || s[l/3]==s[l/3*2]){
        flag=0;return;
    }
}

void out()
{
    if(flag==1){
        printf("YES\n");
    }
    else{
        printf("NO\n");
    }
}

int main()
{
    //freopen("data.in","r",stdin);
    //scanf("%d",&T);
    //for(int cnt=1;cnt<=T;cnt++)
    //while(T--)
    while(scanf("%s",s)!=EOF)
    {
        ini();
        solve();
        out();
    }
}