#include <iostream>
#include <cstdio>
#include <vector>
#include <string>
#include <array>
#include <queue>
#include <deque>
#include <set>
#include <list>
#include <map>
#include <stack>
#include <utility>
#include <algorithm>
#include <numeric>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cctype>
#include <cstring>
#include <climits>
#include <bitset>
#include <random>
#include <functional>
#include <sstream>
#include <iomanip>

using namespace std;

#define _CRT_SECURE_NO_WARNINGS
#define rep(i, n) for(int i=0; i<(n); i++)
#define FOR(i, m, n) for(int i=(m);i<(n);i++)
#define SZ(x) ((int)(x).size())
#define all(x) (x).begin(),(x).end()
#define SORT(x) sort((x).begin(),(x).end())
#define REVE(x) reverse((x).begin(),(x).end())
#define mp make_pair
#define pb push_back

typedef vector<int> VI;
typedef vector<string> VS;
typedef vector<vector<int>> VVI;
typedef pair<int, int> PII;
typedef long long LL;

int main() {
	int n, m, p, q;
	cin >> n >> m >> p >> q;

	int one = q * 2 * m + (12 - q)*m;
	int ans = n / one;
	int now = one * ans;
	ans *= 12;
	FOR(i, 1, 13) {
		if (i >= p && i < p + q)now += 2 * m;
		else now += m;
		ans++;
		//printf("%d月:%d枚 ans:%d\n", i, now,ans);
		if (now >= n)break;
	}
	cout << ans << endl;
}