#include <bits/stdc++.h>

using namespace std;
long moves(long n){
    return 2*(n-1);
}
long longestSequence(vector <long> a) {
    //  Return the length of the longest possible sequence of moves.
    unsigned long long seq=0;
    int n=a.size();
    for(int i=0;i<n;i++)
        seq+=moves(a[i]);
    return seq;
}


int main() {
    int n;
    cin >> n;
    vector<long> a(n);
    for(int a_i = 0; a_i < n; a_i++){
       cin >> a[a_i];
    }
    long result = longestSequence(a);
    cout << result << endl;
    return 0;
}