#include <iostream>
#include <string>
using namespace std;

string NumbersToString(int n, int count) {
    string tmp;
    for (int i = 0; i < count; i++) tmp += to_string(n);
    return tmp;
}

int main(int argc, char ** argv) {
    int count[10];
    for (int i = 0; i < 10; i++) count[i] = 0;

    char cur = 'a';
    while (cur != '0')
    {
        cin >> cur;
        int number = int(cur) - '0';
        if (number > 0 && number < 10) count[number] ++;
    }

    int i = 1;
    for (i; i <= 9; i++)
        if (count[i] % 3 != 0) break;
        else count[i] /= 3;

    if (i < 10) cout << "NO";
    else {
        string result;
        for (int i = 1; i <= 9; i++) result += NumbersToString(i, count[i]);
        for (int i = 0; i < 3; i++) cout << result;
    }

    system("pause");
    return 0;
}