#include <bits/stdc++.h>
using namespace std;
typedef  long long int ll;

int n, ans;
int a[100];
int b[100];
int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> n;
    for (int i = 1; i <= n; i++) {
        int t;
        cin >> t;
        a[t]++;
    }
    vector<int> v,vv;
    for (int i = 1; i <= n; i++) {
        if (a[i] == 0)
            v.push_back(i);
        else if (a[i] > 1) {
            for (int k = 1; k < a[i]; k++)
                vv.push_back(i);
        }
    }
    for (int i = 0; i < v.size(); i++) {
        ans += (v[i] - vv[i]);
    }

    cout << ans << endl;

    return 0;
}