func_code_string: #include <bits/stdc++.h>   using namespace std;   unsigned long long F(unsigned long long n) {     if (n < 10) return n;     unsigned long long nn = n;     int firstDig = 0;     while (n) {       firstDig = n % 10;       n /= 10;     }     return (nn / 10) + 9 - (firstDig > (nn % 10));   }   int main() {     unsigned long long x, y;     while (cin >> x >> y) cout << F(y) - F(x - 1) << endl;     return 0;   }   