#include <iostream>
#include <limits>

int main() {
    int min_dist = std::numeric_limits<int>::max(), n_1, n_2, n_3, finish = 0;
    bool start = false;
    std::cin >> n_1 >> n_2;
    while (true) {
        std::cin >> n_3;
        if (n_3 == 0) {
            break;
        }
        if (n_2 > n_1 && n_2 > n_3) {
            if (!start) {
                start = true;
            } else if (finish < min_dist) {
                min_dist = finish;
                finish = 0;
            }
        }
        else if (start == 1) {
            finish += 2;
        }
        n_1 = n_2;
        n_2 = n_3;
    }
    if (min_dist == std::numeric_limits<int>::max()) {
        std::cout << 0;
    } else {
        std::cout << min_dist;
    }
    return 0;
}