#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int a[100005], last[100005], len[100005];
int read()
{
    int x = 0, w = 1;
    char ch = 0;
    while (ch < '0' || ch > '9')
    {
        if (ch == '-')
            w = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9')
    {
        x = x * 10 + (ch - '0');
        ch = getchar();
    }
    return x * w;
}
int main()
{
    int n;
    scanf("%d", &n);
    for (int i = 0; i < n; i++)
        a[i] = read();
    sort(a, a + n);
    int ans = 100001;
    int last_group = -1;
    for (int i = 0; i < n; i++)
    {
        int index = lower_bound(last, last + last_group + 1, a[i] - 1) - last;
        while (index < last_group && last[index + 1] == a[i] - 1)
            index++;
        if (index > last_group)
        {
            last_group++;
            last[last_group] = a[i];
            len[last_group]++;
        }
        else
        {
            last[index] = a[i];
            len[index]++;
        }
    }
    for (int i = 0; i <= last_group; i++)
        ans = min(ans, len[i]);
    cout << ans;
    return 0;
}