#!/bin/python3

import sys

def howManyGames(p, d, m, s):
    # Return the number of games you can buy
    l = list()
    count = 0
    #s = s - p
    
    #count = 1
    
    while s > 0:
        if (p - d >m ):
            s = s-p
            p = p-d
            if(s>=0):
                count = count + 1
        elif (p-d<=m):
            s = s-p
            p = m
            #s = s-p
            if(s>=0):
                count = count + 1
        if (s-p<0):
            break
    return count
    #while (s>0):
        
    

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)