from itertools import * from bisect import * from collections import * from heapq import * import sys sys.setrecursionlimit(10 ** 6) def II(): return int(sys.stdin.readline()) def MI(): return map(int, sys.stdin.readline().split()) def LI(): return list(map(int, sys.stdin.readline().split())) def SI(): return sys.stdin.readline()[:-1] def LLI(rows_number): return [LI() for _ in range(rows_number)] def LLI1(rows_number): return [LI1() for _ in range(rows_number)] int1 = lambda x: int(x) - 1 def MI1(): return map(int1, sys.stdin.readline().split()) def LI1(): return list(map(int1, sys.stdin.readline().split())) p2D = lambda x: print(*x, sep="\n") dij = [(1, 0), (0, 1), (-1, 0), (0, -1)] import math def main(): l,r,m,k=MI() mn=l*k mx=r*k if k==0 or mx-mn+1>=m or mn%m==0 or mx%m