#pragma GCC target("sse4")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <stdio.h>
#include <algorithm>


unsigned char a[200000];
int n;
using ll = long long;

int main() {
    scanf("%d", &n);
    for (int i = 0; i < n; i++) {
        int temp;
        scanf("%d", &temp);
        a[i] = 1 << std::min(temp - 1, 2);
    }
    ll ans = 0;
    for (int j = 0; j < n; j++) {
        unsigned char t = a[j];
        for (int i = 0; i < j-1; i++) {
            ans += __builtin_ffs(~(t | a[i])) + __builtin_ffs(~(t | a[++i]));
        }
        if ((j&1) == 1) {
            ans += __builtin_ffs(~(t | a[j - 1]));
        }
    }
    printf("%lld\n", ans);
}