#include <iostream>
#include <cstdio>
using namespace std;
int a[1<<17], ans, n, pr[32], cnt, Max;
bool check(){
    bool used[32];
    for(int i = 0; i <= Max; i++)
        used[i] = false;
    for(int i = 1; i <= cnt; i++)
        if(used[pr[i]] && pr[i] != pr[i-1]) return false;
        else used[pr[i]] = true;
    return true;
}
int main(){
    scanf("%d", &n);
    for(int i = 1; i <= n; i++)
        scanf("%d", a+i),
        Max = max(Max, a[i]);
    if(n <= 16){
        ans = n;
        for(int mask = 1; mask < (1<<n); mask++){
            cnt = 0;
            for(int i = n; i >= 1; i--)
                if((1<<(i-1)) & mask) pr[++cnt] = a[i];
            if(check()) ans = min(ans, n - cnt);
        }
    }
    else {

    }
    printf("%d\n", ans);
    return 0;
}
