func_code_string: #include <bits/stdc++.h>   using namespace std;   long long int dig(long long int n) {     long long int r = 0;     while (n) {       ++r;       n = n / 10;     }     return (r - 1);   }   long long int func(long long int n) {     if (n <= 9) return (n + 1);     long long int lt = dig(n);     lt = pow(10, lt);     long long int ret = lt - 1;     long long int mul = ret / 10;     long long int mid = (n % lt) / 10;     lt = n / lt;     long long int rt = n % 10;     if (rt >= lt) {       return (lt * (mul + 1) + func(ret));     } else {       return (lt * (mul + 1) + func(ret));     }   }   long long int fun(long long int n) {     if (n <= 9) return (n + 1);     long long int lt = dig(n);     lt = pow(10, lt);     long long int ret = lt - 1;     long long int mul = ret / 10;     long long int mid = (n % lt) / 10;     lt = n / lt;     long long int rt = n % 10;     if (rt >= lt) {       return ((mid + 1) + (lt - 1) * (mul + 1) + func(ret));     } else {       return (mid + (lt - 1) * (mul + 1) + func(ret));     }   }   int main() {     long long int l, r;     cin >> l >> r;     cout << fun(r) - fun(l - 1);     return 0;   }   