#!/bin/python3=


def howManyGames(p, d, m, s):
    count=0
    while s>=p and p>=m:
        #print("s="+str(s))
        #print("p="+str(p))
        #print("count="+str(count))
        
        count+=1
        s=s-p
        
        if p-d<m:
            p=m
            
        else:
            p=p-d
        
        
    return count
    

if __name__ == "__main__":
    p, d, m, s = input().strip().split(' ')
    p, d, m, s = [int(p), int(d), int(m), int(s)]
    answer = howManyGames(p, d, m, s)
    print(answer)