package baekjoon.그리디;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.Comparator;
class Main10610 {
public static void main(String[] args) throws Exception {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String s = br.readLine();
Character[] a = new Character[s.length()];
int sum = 0;
boolean checkZero = false;
for (int i = 0; i < s.length(); i++) {
a[i] = s.charAt(i);
if (a[i] != '0') {
sum += a[i] + '0';
} else {
checkZero = true;
}
}
Arrays.sort(a, Comparator.reverseOrder());
if (sum % 3 == 0 && checkZero) {
print(a);
} else {
System.out.println(-1);
}
}
public static void print(Character[] a) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < a.length; i++) {
sb.append(a[i]);
}
System.out.println(sb);
}
}