import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		long[] a = new long[5];
		for (int i = 0; i < a.length; i++) {
			a[4 - i] = Long.parseLong(br.readLine());
		}
		br.close();

		long f1 = 0;
		long f2 = 1;
		int i = 0;
		int ans = 0;
		if (a[0] == 1) {
			ans++;
			i++;
		}
		while (i < 5) {
			long n = f1 + f2;
			if (n == a[i]) {
				ans++;
				i++;
			} else if (ans > 0 || n > a[i]) {
				break;
			}
			f1 = f2;
			f2 = n;
		}
		System.out.println(ans);
	}
}