#include <stdio.h>

typedef struct {int n,z;} NZ;

char c;
NZ r(void)
{
  NZ a = {0,0};
  if (scanf(" %c", &c) == 0) return a;

  if (c=='V') {
    a.n = 1;
    a.z = 1;
  }
  else if (c=='U') {
    NZ x = r(), y = r();
    a.n = x.n + y.n;
    a.z = x.z; if (y.z > a.z) a.z = y.z;
  }
  else if (c=='C') {
    NZ x = r();    
    a.n = x.z;
    a.z = x.n;  
  }
  return a;
}


int main(void)
{
  int n;
  while (n = (r()).n, n != 0) {
    c = getchar();
    printf("%d\n", n);
  }
  return 0;
}