Problem:
Score : 300 points

Problem Statement

AtCoDeer the deer and his friend TopCoDeer is playing a game.
The game consists of N turns.
In each turn, each player plays one of the two gestures, Rock and Paper, as in Rock-paper-scissors, under the following condition:

(※) After each turn, (the number of times the player has played Paper)≦(the number of times the player has played Rock).

Each player's score is calculated by (the number of turns where the player wins) - (the number of turns where the player loses), where the outcome of each turn is determined by the rules of Rock-paper-scissors.

(For those who are not familiar with Rock-paper-scissors: If one player plays Rock and the other plays Paper, the latter player will win and the former player will lose. If both players play the same gesture, the round is a tie and neither player will win nor lose.)

With his supernatural power, AtCoDeer was able to foresee the gesture that TopCoDeer will play in each of the N turns, before the game starts.
Plan AtCoDeer's gesture in each turn to maximize AtCoDeer's score.

The gesture that TopCoDeer will play in each turn is given by a string s. If the i-th (1≦i≦N) character in s is g, TopCoDeer will play Rock in the i-th turn. Similarly, if the i-th (1≦i≦N) character of s in p, TopCoDeer will play Paper in the i-th turn.

Constraints

1≦N≦10^5

N=|s|

Each character in s is g or p.

The gestures represented by s satisfy the condition (※).

Input

The input is given from Standard Input in the following format:

s

Output

Print the AtCoDeer's maximum possible score.

Sample Input 1

gpg

Sample Output 1

0

Playing the same gesture as the opponent in each turn results in the score of 0, which is the maximum possible score.

Sample Input 2

ggppgggpgg

Sample Output 2

2

For example, consider playing gestures in the following order: Rock, Paper, Rock, Paper, Rock, Rock, Paper, Paper, Rock, Paper. This strategy earns three victories and suffers one defeat, resulting in the score of 2, which is the maximum possible score.

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;



class Program
{
    const int MOD = 1000000007;
    const int INF = 1 << 30;

    static void Main(string[] args)
    {
        Solve();
    }

    static void Solve()
    {
        Scaner sc = new Scaner();
        write wr = new write();

        string s=sc.Str;
        int pnum=0;
        int gnum=0;
        int winnum=0;
        int losenum=0;
        for(int i=0;i<s.Length;++i){
            if(pnum==gnum){
                gnum++;
                if(s[i]=='p'){
                    losenum++;
                }
            }
            else {
                pnum++;
                if(s[i]=='g'){
                    winnum++;
                }
            }
        }
        wr.wri(winnum-losenum);

    }


    static int factmod(int X){
        int ret=1;
        for(int i=1;i<=X;++i){
            ret*=i;
            ret%=MOD;
        }
        return ret;
    }
}





class Scaner
{
    public string Str => Console.ReadLine();

    public string[] StrArr => Str.Split(' ');

    public long[] LongArr => StrArr.Select(long.Parse).ToArray();
    public int[] IntArr => StrArr.Select(int.Parse).ToArray();
    public char[] CharArr => Str.ToArray();
    public long Long1 => LongArr[0];
    public int Int1 => IntArr[0];
    
}



class write
{
    public  void wri<T>(T x)
    {
        Console.WriteLine(x);
    }
}