#!bin/python3
import sys
def howManyGames(p,d,m,s):
    l=[]
    count=0
    while(p>m):
        if(sum(l)<=s):
            l.append(p)
            p=p-d
            if(p==m):
                break
    while(sum(l)<=s):
                    l.append(m)
    for j in l:
                        count=count+1
    return(count-1)