#include <stdio.h>

#define MAX 48

int getScore(char *s);

int main() {
  char input[MAX];
  int score;

  scanf("%s", input);
  score = getScore(input);
  printf("%d\n", score);

  return 0;
}

/* 请在这里填写答案 */
int getScore(char *s) {
	int score = 0;
	while (*s != '\0') {
		if (*s == 'W') { // Win
			score += 3;
		} else if (*s == 'D') { // Draw
			score += 1;
		} // If lost, the score is unchanged
		s++;
	}
	return score;
}