import math

def main():
    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)

main()