import java.util.HashSet;
import java.util.Set;

class Solution {
	public String nextClosestTime(String current) {
		// Get the digits from input
		Set<Integer> set = new HashSet<>();

		for (int i = 0; i < current.length(); i++) {
			if (current.charAt(i) == ':') continue;
			set.add(Character.getNumericValue(current.charAt(i)));
		}

		// Convert current time to integer representation
		int idx = current.indexOf(':');
		int curr = Integer.valueOf(current.substring(0, idx)) * 60 + Integer.valueOf(current.substring(idx + 1));

		// Going through each time point and validate whether all digits
		// are valid
		int[] result = new int[4];

		// Store each base in an array
		// A number [0, 1440) divide corresponding base gives the digit at that position
		int[] base = new int[] {600, 60, 10, 1};

		for (int i = 1; i <= 1440; i++) {
			// Increment current time incrementally for a full cycle
			int next = (curr + i) % 1440;

			// Check each digit in the next time point
			int j = 0;  // Number of digit are fixed in the result

			while (j < 4) {
				int d = next / base[j];
				if (!set.contains(d)) break;
				result[j] = d;
				next = next % base[j];
				j++;
			}

			if (j == 4) {
				break;
			} else {
				// Clean up
				result = new int[4];
			}
		}

		return String.valueOf(result[0]) + String.valueOf(result[1]) + ":" + String.valueOf(result[2]) + String.valueOf(result[3]);
	}
}