use proconio::{input, marker::Chars};

fn main() {
    input! { s: Chars, };
    let sz = s.len();
    let mut poncount = 0;
    let mut painbool = false;
    for i in 0..sz-4 {
        if s[i..i+3] == ['p', 'o', 'n'] {
            poncount += 1;
        }
        if s[i..i+4] == ['p', 'a', 'i', 'n'] {
            painbool = true;
            break;
        } 
    }
    if painbool {
        println!("{}", poncount);
    } else {
        println!("-1");
    }
}