T = int(input())
X,A = map(int, input().split())
Y,B = map(int, input().split())
ans = 10**20
for y in range(10**7+10):
    before = -T-y*B
    if before<=0:
        x = abs(before)//A
        ans = min(ans,y*Y-before,y*Y+x*X+abs(T-(y*A-x*B)))
print(ans)