Codeforces_758A

// Codeforces 758A

#include <iostream>

using namespace std;

int main()
{
    int n, maxim = 0, rez = 0;
    cin >> n;
    int nn[n];
    for( int i = 0; i < n; i++ )
    {
        cin >> nn[i];
        if ( nn[i] > maxim ){ maxim = nn[i]; }
    }
    for( int y = 0; y < n; y++ )
    {
        if ( nn[y] < maxim ){ rez += maxim - nn[y];}
    }
    cout << rez;
    return 0;
}