#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll = long long;
#define int ll
#define rng(i, a, b) for (int i = int(a); i < int(b); i++)
#define rep(i, b) rng(i, 0, b)
#define ALL(a) (a).begin(), (a).end()
template <class t, class u> void chmax(t& a, u b) {
    if (a < b) a = b;
}
template <class t, class u> void chmin(t& a, u b) {
    if (b < a) a = b;
}
template <class t> using vc = vector<t>;
template <class t> using vvc = vc<vc<t>>;
using pi = pair<int, int>;
using vi = vc<int>;
using uint = unsigned;
using ull = unsigned long long;
int popcount(signed t) { return __builtin_popcount(t); }
int popcount(ll t) { return __builtin_popcountll(t); }
bool ispow2(int i) { return i && (i & -i) == i; }
ll mask(int i) { return (ll(1) << i) - 1; }
int lcm(int a, int b) { return a / __gcd(a, b) * b; }
signed main() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(20);
    string s;
    cin >> s;
    s+="q";
    int pn = 0, ponn = 0;
    for (int i = 0; i < s.size() - 3; i++) {
        if (pn == 0) {
            if (s[i] == 'p' && s[i + 1] == 'o' && s[i + 2] == 'n') {
                ponn++;
            }
        }
        if (s[i] == 'p' && s[i + 1] == 'a' && s[i + 2] == 'i' &&
            s[i + 3] == 'n') {
            pn++;
            break;
        }
    }
    if (pn == 0) {
        cout << -1 << endl;
        return 0;
    }
    if (ponn < 2) {
        cout << -1 << endl;
        return 0;
    }
    cout << ponn - 1 << endl;
}