func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long long int n, i, num, prev = 0, total = 0;     cin >> n;     for (i = 0; i < n; i++) {       cin >> num;       if (num - prev < 0) total += abs(num - prev);       prev = num;     }     cout << total;     return 0;   }   