public class ValidDNA {

	// Notkun: c = isValidDNA(s);
	// Fyrir: ekkert
	// Eftir: c er true ef einu stafirnir i s eru A,C,G,T
	public static boolean isValidDNA(String s) {

		boolean valid = true;

		for (int i = 0; i < s.length(); i++) {
			// I: valid is true if all characters from 0 to i-1
			// in s are one of A,C,G or T

			char c = s.charAt(i);

			if (c != 'A' && c != 'C' && c != 'G' && c != 'T') {
				valid = false;
			}
		}

		return valid;
	}

	public static void main(String[] args) {

		System.out.println(isValidDNA(args[0]));
	}
}