//uva12869 #include <iostream> using namespace std; int main() { long long int low, high, low_zeros, high_zeros; while (cin >> low >> high) { if (low == 0 && high == 0) break; low_zeros = 0; high_zeros = 0; low_zeros = low_zeros + (low / 5); high_zeros = high_zeros + (high / 5); cout << high_zeros - low_zeros + 1 << endl; } return 0; }