Problem:
Score : 500 points

Problem Statement

A robot is put at the origin in a two-dimensional plane.
Initially, the robot is facing in the positive x-axis direction.

This robot will be given an instruction sequence s.
s consists of the following two kinds of letters, and will be executed in order from front to back.

F : Move in the current direction by distance 1.

T : Turn 90 degrees, either clockwise or counterclockwise.

The objective of the robot is to be at coordinates (x, y) after all the instructions are executed.
Determine whether this objective is achievable.

Constraints

s consists of F and T.

1 \leq |s| \leq 8 000

x and y are integers.

|x|, |y| \leq |s|

Input

Input is given from Standard Input in the following format:

s
x y

Output

If the objective is achievable, print Yes; if it is not, print No.

Sample Input 1

FTFFTFFF
4 2

Sample Output 1

Yes

The objective can be achieved by, for example, turning counterclockwise in the first T and turning clockwise in the second T.

Sample Input 2

FTFFTFFF
-2 -2

Sample Output 2

Yes

The objective can be achieved by, for example, turning clockwise in the first T and turning clockwise in the second T.

Sample Input 3

FF
1 0

Sample Output 3

No

Sample Input 4

TF
1 0

Sample Output 4

No

Sample Input 5

FFTTFF
0 0

Sample Output 5

Yes

The objective can be achieved by, for example, turning counterclockwise in the first T and turning counterclockwise in the second T.

Sample Input 6

TTTT
1 0

Sample Output 6

No

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Time Limit Exceeded)

import java.util.Arrays;
import java.util.Scanner;
import java.util.stream.IntStream;

/**
 * 解説どおりに作成したソースコード
 */
public class Main {

	/** 方向変換するときの文字 */
	private static final char TRANSFER = 'T';

	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			char[] s = scanner.next().toCharArray();
			int x = scanner.nextInt();
			int y = scanner.nextInt();
			int[][] step = new int[2][s.length / 2 + 1];
			IntStream.range(0, 2).forEach(i -> Arrays.fill(step[i], 0));
			// X軸ステップとY軸ステップ数の数
			int[] number = new int[2];
			number[0] = 0;
			number[1] = 1;
			int current = 0;
			int count = 0;
			for (char c : s) {
				if (TRANSFER == c) {
					step[current][number[current]] = count;
					number[current]++;
					count = 0;
					current = 1 - current;
				} else {
					count++;
				}
			}
			if (count > 0) {
				step[current][number[current]] = count;
				number[current]++;
			}
			System.out.println((ok(number[0] - 1, step[0], x) && ok(number[1] - 1, step[1], y)) ? "Yes" : "No");
		}
	}

	/**
	 * あるステップ数後に目的地が達成できるかどうかを計算
	 * 
	 * @param index       ステップ数（0-index）
	 * @param step        ステップ一覧
	 * @param destination 目的値
	 * @return あるステップ数後に目的地が達成できるかどうか
	 */
	private static boolean ok(final int index, final int[] step, final int destination) {
		if (0 == index) {
			return step[0] == destination;
		}
		return ok(index - 1, step, destination - step[index]) || ok(index - 1, step, destination + step[index]);
	}
}