gistfile1.txt

#include <iostream>
#include <vector>

using namespace std;

int minCoupons(vector<int>& a) {
    int n = a.size();
    int coupons = 0;
    int prev = a[0]; 

    for (int i = 1; i < n; i++) {
        if (a[i] < prev) {
            int diff = prev - a[i];
            int k = 1; 

            while (k < n && k + 1 <= diff) {
                k++;
            }

            coupons += k + 1; 
            a[i] = prev; 
        } else {
            prev = a[i]; 
        }
    }

    return coupons;
}

int main() {
    int n;
    cin >> n;

    vector<int> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }

    int result = minCoupons(a);

    // Output Format: a single integer
    cout << result << endl; 

    return 0;
}