def corect (S):
    n = 0
    for i in range (1, 12):
        temp = S//(5**i)
        n += temp
        if temp == 0:
            break
    return n

inpput = open("fact.in", "r")
ouut = open ("fact.out", "w")
P = int(inpput.readline())
if (P == 0):
	ouut.write("1")
    #inpput.close()
    #ouut.close()
	#exit(0)
else:
    temp = 5*P
    while corect(temp) > P:
        temp -= 5
    if corect(temp) == P:
        temp = str(temp)
        ouut.write(temp)
    else:
        ouut.write("-1")
inpput.close()
ouut.close()
exit(0)