func_code_string: #include <bits/stdc++.h>   using namespace std;   int gcd(int a, int b) {     while (b) {       a %= b;       swap(a, b);     }     return a;   }   int main() {     int n;     scanf( %d , &n);     vector<int> a;     int r2 = 0;     int ans;     int prev = 0;     long long res = 0;     int pr2 = 0;     for (int i = 0; i < n; i++) {       int tmp;       scanf( %d , &tmp);       if (i == 0) {         prev = tmp;         continue;       }       if (tmp < prev) {         res += prev - tmp;       }       prev = tmp;     }     printf( %I64d , res);     return 0;   }   