#include<bits/stdc++.h>
#define ALL(v) std::begin(v),std::end(v)
using lint=long long;
using lubl=long double;
void cmn(lint&x,lint y){if(x>y)x=y;}
int main(){
    std::cin.tie(nullptr);std::ios_base::sync_with_stdio(false);
    std::cout.setf(std::ios_base::fixed);std::cout.precision(15);
    lint n;std::cin>>n;
    std::vector<lint>a(n);
    for(lint&x:a)std::cin>>x;
    std::sort(ALL(a));
    lint m=*std::max_element(ALL(a))+1;
    std::vector<lint>primes;
    {
        std::vector<lint>sieve(m+1);
        for(lint p=2;p<=m;p++){
            if(sieve.at(p))continue;
            primes.push_back(p);
            for(lint i=p*p;i<=m;i+=p)sieve.at(i)=true;
        }
    }
    std::vector<lint>dp(m),ep(m,-1);
    for(lint len=0;;len++){
        dp.assign(m,n);
        for(lint i=n-1;i>=0;i--){
            if(i<=ep.at(a.at(i)))continue;
            dp.at(a.at(i))=i;
        }
        if(std::all_of(ALL(dp),[n](lint x){return x==n;})){
            std::cout<<len<<'\n';
            return 0;
        }
        ep.assign(m,n);
        for(lint p:primes){
            for(lint i=1;i<=(m-1)/p;i++){
                cmn(ep.at(i*p),dp.at(i));
            }
        }
        for(lint p:primes){
            for(lint i=1;i<=(m-1)/p;i++){
                cmn(ep.at(i*p),ep.at(i));
            }
        }
    }
}