import math

people = int(input())
infectPeople = int(input())
recoveryDay = int(input())
protectedRate = float(input())
periodWeek = int(input())
waitRecovery = [0]*recoveryDay + [people]
target = float('inf')

for i in range(periodWeek):
    thisWeekInfect, thisWeekNewInfect, thisWeekRecovery = 0, 0, 0
    for j in range(7):
        if i == 0 and j == 0:
            thisWeekNewInfect += people
            thisWeekInfect += people
            continue
        waitRecovery.append(int(people*(infectPeople/recoveryDay)*(1-protectedRate)))
        people = people + waitRecovery[-1] - waitRecovery[i*7+j]
        thisWeekNewInfect += waitRecovery[-1]
        thisWeekInfect += people
        thisWeekRecovery += waitRecovery[i*7+j]
    averageWeekNewInfect = math.ceil(thisWeekNewInfect/7)
    print(f'(Week {i+1}, {math.ceil(thisWeekInfect/7)}, {averageWeekNewInfect}, {math.ceil(thisWeekRecovery/7)})')
    if averageWeekNewInfect == 0:
        target = min(target, i+1)

print(target)