import bisect,collections,copy,heapq,itertools,math,string,sys,queue
from decimal import Decimal
def I(): return input()
def IS(): return input().split()
def II(): return int(input())
def IIS(): return map(int,input().split())
def LIIS(): return list(map(int,input().split()))
def ZER(N): return [False for _ in range(N)]
INF=float("inf")
MOD=10**9+7
#　　　　　V
#　　 ／￣ψ￣＼
#　　| 合格祈願 |
#　　|＿＿＿＿＿|
##############################################################################
a,b,c,d,e=IIS()
com=b-c
li=[0]*(com*a)
if com==0:
    print(0)
    exit()
li[0]=d
for i in range(1,com*a):
    x=li[i-1]
    if (i+1)%10!=0:
        li[i]=x
    elif (i+1)%10==0 and e<=x:
        li[i]=x-e
    else:
        li[i]=x
print(sum(li))