#include <stdio.h>
#include <stdlib.h>

int min(int x, int y)
{
    int min=x;
    if(min>y)
        return y;
    return x;
}

int nzd(int x, int y)
{
    int proizvod=1,i;
    for(i=1;i<=min(x,y);++i)
    {
        if((x%i==0) && (y%i==0))
            proizvod=i;
    }
    return proizvod;
}



int main()
{
    int n,a[100],result=0,i,resenie=0;
    scanf("%d",&n);
    for(i=0;i<n;++i)
    {
        scanf("%d",&a[i]);
    }
    for(i=0;i<n-2;++i)
    {
        result=min(nzd(a[i],a[i+1]),nzd(a[i+1],a[i+2]));
        resenie=min(result,nzd(a[i+2],a[i+3]));
    }
    printf("%d",result);
    return 0;
}