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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)


import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);

		char[] input = sc.next().toCharArray();

//		int g[] = new int[input.length];
//		int p[] = new int[input.length];
//
//		for(int i = 1; i < input.length; i++){
//			if(input[i - 1] == 'g'){
//				g[i] = g[i - 1] + 1;
//				p[i] = p[i - 1];
//			}
//			else {
//				g[i] = g[i - 1];
//				p[i] = p[i - 1] + 1;
//			}
//
//			System.out.println(g[i] + " " + p[i]);
//		}

		int result = 0;
		int p = 0;
		int g = 1;
		for(int i = 1; i < input.length; i++){
//			if(input[i] == 'g' && p[i] + 1 <= g[i]){
			if(input[i] == 'g' && p + 1 <= g){
//				System.out.println("i = "+i);
				result++;
				p++;
			}
			else {
				g++;

				if(input[i] == 'p'){
					result--;
				}
			}

//			System.out.println("g "+g+" p "+p);
		}

		System.out.println(result);
	}

}