#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i,n) for(int i=0;i<n;i++)
#define krep(i,k,n,m) for(int i=k;i<n;i+=m)
#define erep(i,k,n) for(int i=k;i<n;i++)
#define mod 1000000007;
//最大公約数
int gcd(int s,int b){
    if(b==0)return s;
    return gcd(b,s%b);
}
signed main(){
    int n;
    cin>>n;
    int a[n];
    int ans=0;
    rep(i,n){
        cin>>a[i];
        ans+=a[i];
    }
    int kai=(1+n)*n/2;
    cout<<ans-kai<<endl;
}


### Prompt

Please provide a CPP coded solution 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 int long long
#define rep(i,n) for(int i=0;i<n;i++)
#define krep(i,k,n,m) for(int i=k;i<n;i+=m)
#define erep(i,k,n) for(int i=k;i<n;i++)
#define mod 1000000007;
//最大公約数
int gcd(int s,int b){
    if(b==0)return s;
    return gcd(b,s%b);
}
signed main(){
    int n;
    cin>>n;
    int a[n];
    int ans=0;
    rep(i,n){
        cin>>a[i];
        ans+=a[i];
    }
    int kai=(1+n)*n/2;
    cout<<ans-kai<<endl;
}


```