#include <limits> #include <iostream> #include <algorithm> #include <vector> #include <iomanip> #include <map> #include <queue> static const int MOD = 1000000007; using ll = long long; using u32 = unsigned; using namespace std; template<class T> constexpr T INF = ::numeric_limits<T>::max() / 32 * 15 + 208; int main() { int n, m, p, q; cin >> n >> m >> p >> q; int s = 1; while(n > 0){ if((s-1)%12+1 >= p && (s-1)%12+1 <= p+q-1) n -= 2*m; else n -= m; if(n > 0) s++; } cout << s << "\n"; return 0; }