#include <cstdlib>
#include <iostream>

using namespace std;

long long int dani[5000];
bool dolazi[5000];

int main()
{
    int brb=0, n;
    long long int dan;
    cin >> n;
    for ( int i = 1; i <= n; ++i )
    {
        cin >> dan;
        dani[i] = dan-1;
    }
    for ( int i = 2; i < n; ++i )
    {
        if ( dani[n]%dani[i] == 0 && dolazi[i] == false )
        {
            ++brb;
            for ( int j = i; j < n; ++j )
                if ( dani[j]%dani[i] == 0 && dani[j] == false )
                    dolazi[i] = true;
        }
    }
    cout << brb << endl;
}