#include<stdio.h>
#include<iostream>
#include<string>
#include<string.h>
#include<math.h>
#include<algorithm>

using namespace std;

int main() {
	int l, r;
	while (cin >> l >> r) {
		int count = 0;
		for (int i = l; i <= r; i++)
		{
			if (i % 10 == 2)
				count++;
			if (i / 10 == 2)
				count++;
			if (i / 100 == 2)
				count++;
			if (i / 1000 == 2)
				count++;
			if (i / 10000 == 2)
				count++;
			if (i / 100000 == 2)
				count++;
		}
		cout << count << endl;
	}
	return 0;
}