#include <bits/stdc++.h>
using namespace std;
long long N;
long long get_max(vector<long long> A, long long left, long long right) {
    if (A.empty())
        return -1;
    if (right - left == 0)
        return A[left];
    if ((right - left) <= 1) {
        if (A[left] > A[right])
            return A[left];
        return A[right];
    }
    int middle = (right - left) / 2 + left;
    int max_left = get_max(A, left, middle);
    int max_right = get_max(A, middle + 1, right);
    if (max_left > max_right)
        return max_left;
    else
        return max_right;
}
long long main() {
    scanf("%lld", &N);
    vector<long long> A(N);
    for (int i = 0; i < N; i++) scanf("%lld", &A[i]);
    long long minSteps = 0;
    long long maxVal = get_max(A, 0, N - 1);
    for (int i = 0; i < N; i++) {
        int diff = maxVal - A[i];
        minSteps += diff;
    }
    printf("%lld", minSteps);
    return 0;
}

/sandbox/1/a.cpp:20:1: error: 'main' must return 'int'
long long main() {
^~~~~~~~~
int
1 error generated.