#include <bits/stdc++.h>
#define show(x) std::cerr << #x << " = " << x << std::endl
using ll = long long;
using ull = unsigned long long;
using ld = long double;
constexpr ll MOD = 1000000007LL;
template <typename T>
constexpr T INF = std::numeric_limits<T>::max() / 10;
std::mt19937 mt{std::random_device{}()};
int main()
{
    int N, M, P, Q;
    std::cin >> N >> M >> P >> Q;
    for (int j = 0;; j++) {
        const int i = 1 + (j % 12);
        const int m = (i >= P and i < P + Q) ? 2 * M : M;
        N -= m;
        if (N <= 0) { return std::cout << j + 1 << std::endl, 0; }
    }
    return 0;
}