#include <bits/stdc++.h>
using namespace std;
#define REP(i,a) for(int i = 0; i < (a); i++)
#define ALL(a) (a).begin(),(a).end()
typedef long long ll;
typedef pair<int, int> P;
const int INF = 1e9;
const long long LINF = 1e18;
const long long MOD = 1e9 + 7;

signed main(){
    int n;
    cin >> n;
    ll ans = 0;
    int v;
    REP(i,n){
        cin >> v;
        ans += v;
        ans -= i + 1;
    }
    cout << ans << endl;
    return 0;
}

### Prompt

Develop a solution in cpp to the problem described below:

Gag

Segtree has $ N $ of "gags", each with a value of $ V_i $.

Segtree decided to publish all the gags in any order.

Here, the "joy" you get when you publish the $ i $ th gag to the $ j $ th is expressed as $ V_i --j $.

Find the maximum sum of the "joy" you can get.

input

Input is given from standard input in the following format.


$ N $
$ V_1 $ $ V_2 $ $ \ ldots $ $ V_N $


output

Please output the maximum value of the sum of "joy". However, the value does not always fit in a 32-bit integer.

Insert a line break at the end.

Constraint

* $ 1 \ leq N \ leq 10 ^ 5 $
* $ 1 \ leq V_i \ leq 10 ^ 5 $
* All inputs are integers.



Input example 1


1
59549


Output example 1


59548


Input example 2


Five
2 1 8 5 7


Output example 2


8






Example

Input

1
59549


Output

59548

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
#define REP(i,a) for(int i = 0; i < (a); i++)
#define ALL(a) (a).begin(),(a).end()
typedef long long ll;
typedef pair<int, int> P;
const int INF = 1e9;
const long long LINF = 1e18;
const long long MOD = 1e9 + 7;

signed main(){
    int n;
    cin >> n;
    ll ans = 0;
    int v;
    REP(i,n){
        cin >> v;
        ans += v;
        ans -= i + 1;
    }
    cout << ans << endl;
    return 0;
}

```