#include<stdio.h>
int main()
{
	char s[200005];
	scanf("%s", s);
	int i, n;
	for (n = 0; s[n] != '\0'; n++);
	int left = n;
	for (i = n - 1; i > 2; i--)
		if (s[i - 3] == 'p' && s[i - 2] == 'a' && s[i - 1] == 'i' && s[i] == 'n')
			left = i - 3;
	if (left == n)
	{
		printf("-1\n");
		return 0;
	}
	int cnt = 0;
	for (i = 0; i < left; i++)
		if (s[i] == 'p' && s[i + 1] == 'o' && s[i + 2] == 'n')
			cnt++;
	if (cnt > 1)
		printf("%d\n", cnt - 1);
	else
		printf("-1\n");
	return 0;
}