#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:66777216")
using namespace std;
const long long INF = 1e18, MOD = 1e9 + 7, MAXN = 31, MAXK = 51;
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
signed main() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  string s;
  cin >> s;
  long long n = s.length(), sum = 0, z = 0;
  if (n == 1) {
    if ((s[0] - '0') % 3 == 0) {
      cout << s;
    } else {
      cout << -1;
    }
    return 0;
  }
  vector<long long> f(n);
  for (long long i = 0; i < n; i++) {
    if (s[i] == '0') z++;
    f[i] = (s[i] - '0') % 3;
    sum += f[i];
  }
  if (sum % 3 == 0) {
    cout << s;
    return 0;
  }
  if (sum % 3 == 1) {
    long long it = -1;
    for (long long i = 0; i < n; i++) {
      if (f[i] == 1) {
        it = i;
      }
    }
    if (it > 0 || it == 0 && s[1] != '0') {
      for (long long i = 0; i < n; i++) {
        if (i != it) cout << s[i];
      }
      return 0;
    }
    long long it1 = -1, it2 = -1;
    for (long long i = 0; i < n; i++) {
      if (f[i] == 2) {
        it2 = it1;
        it1 = i;
      }
    }
    if (it1 == -1 || it2 == -1 || n == 2) {
      if (it != -1) {
        bool flag = 0;
        for (long long i = 1; i < n; i++) {
          if (s[i] != '0') {
            flag = 1;
            cout << s[i];
          } else {
            if (flag) cout << s[i];
          }
        }
        if (!flag) cout << 0;
        return 0;
      }
      cout << -1;
      return 0;
    }
    bool flag = 0;
    for (long long i = 0; i < n; i++) {
      if (s[i] == '0' && !flag) continue;
      if (i != it1 && i != it2) {
        flag = 1;
        cout << s[i];
      }
    }
    if (!flag && !z)
      cout << -1;
    else if (!flag)
      cout << 0;
    return 0;
  } else {
    long long it = -1;
    for (long long i = 0; i < n; i++) {
      if (f[i] == 2) {
        it = i;
      }
    }
    if (it > 0 || it == 0 && s[1] != '0') {
      for (long long i = 0; i < n; i++) {
        if (i != it) cout << s[i];
      }
      return 0;
    }
    long long it1 = -1, it2 = -1;
    for (long long i = 0; i < n; i++) {
      if (f[i] == 1) {
        it2 = it1;
        it1 = i;
      }
    }
    if (it1 == -1 || it2 == -1 || s.length() == 2) {
      if (it != -1) {
        bool flag = 0;
        for (long long i = 1; i < n; i++) {
          if (s[i] != '0') {
            flag = 1;
            cout << s[i];
          } else {
            if (flag) cout << s[i];
          }
        }
        if (!flag) cout << 0;
        return 0;
      }
      cout << -1;
      return 0;
    }
    bool flag = 0;
    for (long long i = 0; i < n; i++) {
      if (s[i] == '0' && !flag) continue;
      if (i != it1 && i != it2) {
        cout << s[i];
        flag = 1;
      }
    }
    if (!flag && !z)
      cout << -1;
    else if (!flag)
      cout << 0;
    return 0;
  }
}
