s = input().strip()

# Find the first occurrence of 'pain'
pain_start = s.find('pain')

if pain_start == -1:
    print(-1)
else:
    # Extract the substring before the first 'pain'
    substring = s[:pain_start]
    count = 0
    # Iterate through the substring to count 'pon's
    for i in range(len(substring) - 2):
        if substring[i] == 'p' and substring[i+1] == 'o' and substring[i+2] == 'n':
            count += 1
    if count < 2:
        print(-1)
    else:
        print(count - 1)