import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.*;

public class jeroen {
	static BufferedReader in = new BufferedReader(new InputStreamReader(System.in));

	static int gap10 = 0;
	static int gap11 = 0;
	static int gap20 = 0;
	static int gap22 = 0;
	
	public static void main(String[] args) throws Exception {
		// Read input
		String[] ps = in.readLine().split(" ");
		int n = Integer.valueOf(ps[0]);
		int s = Integer.valueOf(ps[1]);
		int[] w = new int[n];
		ps = in.readLine().split(" ");
		for(int i = 0; i < n; i++)
			w[i] = Integer.valueOf(ps[i]);

		// Sort and plug in both ends first
		Arrays.sort(w);
		if (n == 1 || s == 1) {
			System.out.println("1");
			return;
		}
		int res = 2;
		n -= 2;
		s -= 2;

		// Now fill from small to big, and if we make gaps
		// we keep that info so that we can swap in some
		// other adaptor later. We only need to keep that
		// info modulo 3.
		for(int i = 0; i < n; i += 2) {
			// Get the adapter, see if we can swap it into
			// an earlier gap, and count the number of sockets
			int c1 = swapAdapter(w[i]);
			int s1 = (c1 + 2) / 3;

			// Check if this plug still fits
			if(s1 > s) break;
			res++;
			s -= s1;

			// Now place the next one opposite
			if(i + 1 < n) {
				int c2 = swapAdapter(w[i+1]);
				int s2 = (c1 + c2 + 2) / 3 - s1;

				if(s2 > s) break;
				s -= s2;
				res++;

				// See if we made a gap
				if((c1 % 3) + (c2 % 3) == 2) {
					if((c1 % 3) == 0 || (c2 % 3) == 0)
						gap20++;
					else
						gap11++;
				} else if((c1 % 3) + (c2 % 3) == 1) {
					gap10++;
				} else if((c1 % 3) + (c2 % 3) == 4) {
					gap22++;
				}
			}
		}
		System.out.println(res);
	}

	static int swapAdapter(int w) {
		if(w % 3 == 2 && gap10 > 0) {
			w -= 2;
			gap10--;
		} else if (w % 3 == 1 && gap22 > 0) {
			w -= 2;
			gap22--;
		} else if (w % 3 == 2 && gap11 > 0) {
			w -= 1;
			gap11--;
		} else if (w % 3 == 1 && gap20 > 0) {
			w -= 1;
			gap20--;
		} else if (w % 3 == 1 && gap10 > 0) {
			w -= 1;
			gap10--;
			gap11++;
		}
		return w;
	}
}