#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

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

    q = p + q - 1;

    int y = 0;
    srep(i,1,13){
        if(p <= i && i <= q)y += m * 2;
        else y += m;
    }

    int ans = 0;

    ans += 12 * (n / y);
    n -= n / y * y;

    srep(i,1,13){
        if(n <= 0)break;
        if(p <= i && i <= q)n -= m * 2;
        else n -= m;
        ans++;
    }

    cout << ans << endl;
    return 0;
}