#include <iostream>
using namespace std;
size_t length(int* box, const size_t n) {
int pattern[] = { 1, 2, 3 };
auto count = 0U;
for (auto i = 0U, j = 0U; i < n; ++i) {
if (box[i] == pattern[j]) ++j;
if (j == size(pattern)) {
count += 3U;
j = 0U;
}
}
return count;
}
int main() {
int box[] = { 1, 4, 2, 3, 5, 1, 1, 3, 2, 5, 6, 3, 1, 2, 0, 3, 1, 2 };
for (auto value : box) cout << ' ' << value;
cout.put('\n');
auto quantity = length(box, size(box));
cout << ' ' << quantity << '\n';
cin.get();
}