#include <stdio.h>
#include <malloc.h>

char str[60000];
int str_len = 0;

/// <summary>
/// グローバル変数strの中身を入力された文字列で上書きする
/// </summary>
void ReadString() {
	char c = getchar();
	str_len = 0;

	while (c != '\n') {
		str[str_len] = c;
		c = getchar();
		str_len++;
	}
}

int main()
{
	ReadString();
	int now = 1;

	for (int i = 0;i < str_len;i++) {
		if (str_len == 0) break;
		now *= 2;
		if (str[i] == 'R') now += 1;
	}
	printf("%d\n", now);
}