import heapq

t=int(input())
x,a=map(int,input().split())
y,b=map(int,input().split())

V={0}

que=[(0,0)]
heapq.heapify(que)

MAX=10**7+100
while 1:
    val,now=heapq.heappop(que)
    if now==t:
        print(val)
        break

    vx=now+a
    if abs(vx)<MAX and not vx in V:
        heapq.heappush(que,(val+x,vx))
        V.add(vx)
    
    vx=now-b
    if abs(vx)<MAX and not vx in V:
        heapq.heappush(que,(val+y,vx))
        V.add(vx)

    vx=now+1
    if abs(vx)<MAX and not vx in V:
        heapq.heappush(que,(val+1,vx))
        V.add(vx)