#include<bits/stdc++.h>
#include<string>
#include<vector>

using namespace std;

typedef long long int ll;
typedef long double ld;
typedef unsigned long long int ull;
typedef long long li;

#define ms(x,a) memset(x,a,sizeof(x))
#define forn(i, n) for (int i = 0; i < int(n); i++)
#define pi      acos(0.0)*2 // 3.1415926535897932
#define mx      100000007
#define mod     1000000007
#define base    10000007
#define pb      push_back
#define mx1     10001000

ull ara[mx];
vector<ull>prime;
vector<ll>prm;

void inOut();
void seive();

int main()
{
    //inOut();
    seive();
    ll i,j,k,l,q,n,m;
    string s;

    cin>>n;
    ll a[n+2];

    for(i=0; i<n; i++)
    {
        cin>>a[i];

        for(j=0; j<prime.size(); j++)
        {
            if(a[i] == prime[j])
            {
                prm.pb(a[i]); break;
            }
        }
    }

    sort(a, a+n);
    sort(prm.begin(), prm.end());
    ll sum = 0, lprm;
    ll sz = prm.size();

    for(i=sz-1; i>=0; i--)
        if(prm[i]<a[n-1])
        {
            lprm = prm[i]; break;
        }

    for(i=n-1; i>=0; i--)
    {
        if(a[i] == lprm)
            continue;
        else
            sum += abs(a[i] - lprm);
    }

    cout<<sum<<endl;

    return 0;
}

void inOut()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    #ifndef ONLINE_JUDGE
        freopen("input.txt", "r", stdin);
        //freopen("output.txt", "w", stdout);
    #endif
}

void seive()
{
    ull i, j, n = mx1, m = n;

    for(i=3; i<=m; i+=2)
    {
        if(ara[i]==0)
        {
            for(j=i*i; j<=n; j+=i*2)
                ara[j] = 1;
        }
    }

    ara[1] = 1;

    for(i=4; i<=n; i+=2)
        ara[i] = 1;

    prime.push_back(1);
    prime.push_back(2);

    for(i=3; i<=n; i+=2)
    {
        if(ara[i]==0)
            prime.push_back(i);
    }
}