import java.util.Arrays;
import java.util.Comparator;
import java.util.PriorityQueue;
import java.util.Scanner;

class Main {

	public static void main(String[] args) {
		new Main().run();
	}

	void run() {
		Scanner sc = new Scanner(System.in);
		int n = 5;
		long[] a = new long[n];
		for (int i = 0; i < n; ++i)
			a[i] = sc.nextLong();
		long[] Fib = new long[74];
		Fib[0] = Fib[1] = 1;
		for (int i = 2; i < Fib.length; ++i) {
			Fib[i] = Fib[i - 1] + Fib[i - 2];
		}
		int ans = 0;
		for (int i = n - 1; i >= 0; --i) {
			int pos = Arrays.binarySearch(Fib, a[i]);
			if (pos < 0)
				continue;
			int sz = 1;
			while (i - sz >= 0 && pos + sz < Fib.length && Fib[pos + sz] == a[i - sz])
				++sz;
			if (i + 1 < n && a[i + 1] == 1)
				++sz;
			ans = Math.max(ans, sz);
		}
		System.out.println(ans);
	}

	void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}
}