#include<bits/stdc++.h>
using namespace std;
#define il inline
#define gc getchar()
#define int long long
#define ri register int
#define rc register char
#define rb register bool
#define lowbit(x) (x&(-x))
#define rp(i,x,y) for(ri i=x;i<=y;++i)
#define my(i,x,y) for(ri i=x;i>=y;--i)

const int N=400+10,inf=1e9;
int n,match[N];
bool vis[N];
vector<int>to[N],V[2];

il int read()
{
    rc ch=gc;ri x=0;rb y=1;
    while(ch!=‘-‘ && (ch>‘9‘ || ch<‘0‘))ch=gc;
    if(ch==‘-‘)ch=gc,y=0;
    while(ch>=‘0‘ && ch<=‘9‘)x=(x<<1)+(x<<3)+(ch^‘0‘),ch=gc;
    return y?x:-x;
}
int gcd(ri x,ri y){return y?gcd(y,x%y):x;}
int dfs(ri x)
{
    vis[x]=1;
    for(auto t:to[x]){if(~match[t])if(vis[match[t]] || !dfs(match[t]))continue;match[t]=x;return 1;}
    return 0;
}

signed main()
{
    n=read();rp(i,1,n){ri x=read();V[x&1].push_back(x);}ri sz0=V[0].size(),sz1=V[1].size();
    rp(i,0,sz0-1)rp(j,0,sz1-1)if(gcd(V[0][i],V[1][j])*gcd(V[0][i]+1,V[1][j]+1)==1)to[i].push_back(j);
    memset(match,-1,sizeof(match));rp(i,0,sz0-1){memset(vis,0,sizeof(vis));n-=dfs(i);}printf("%lld\n",n);  
    return 0;
}