kari=list(input())
A=int(kari[0])
B=int(kari[1])
C=int(kari[2])
D=int(kari[3])

board=[]

for i in range(1,A+1):
    veg = i
    meet = i * C
    total = veg + meet
    
    if  veg <= A and meet <=B and total <= D:
        board.append(veg)
    else:
        break
    
m=-1
for count in board:
    if count >= m:
        m=count

print(m)