let n = readLine()!.split(separator: " ").map{Int($0)!}
let (N,M,P,Q) = (n[0],n[1],n[2],n[3])
var l = [Int](repeating: M, count: 12)
for i in (P-1)...(P+Q-2){
    l[i] += M
}
let y = l.reduce(0){$0 + $1}
var (m,o) = ((N / y) * 12,N % y)
for i in l{
    if o <= 0{break}
    m += 1
    o -= i
}
print(m)