MOD = 10 **9 + 7
INF = 10 ** 10

def main():
    a,b,c,d = map(int,input().split())
    ans = 0
    for x in range(min(a,d),-1,-1):
        y = c*x
        if y <= b and x + y <= d:
            ans = x
            break
    print(ans)             
if __name__ == '__main__':
    main()