s = input()
s2 = s.replace("pain", "Y")
s3 = s2.replace("pon", "X")
# print(s3)

res = -1
ok = False
for c in s3:
    if c == "Y":
        ok = True
        break
    if c == "X":
        res += 1

if res == 0 or not ok:
    res = -1

print(res)