#include <iostream> using namespace std; int countDigit2(int num) { int count = 0; while (num > 0) { if (num % 10 == 2) count++; num /= 10; } return count; } int main() { int L, R; cin >> L >> R; int total_count = 0; for (int i = L; i <= R; i++) { total_count += countDigit2(i); } cout << total_count << endl; return 0; }