#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv) {
  int problems = 0;
  while (1) {


    int start;
    scanf("%d", &start);
    char c;
    scanf("%c", &c);
    if (c == '-') {
      int end;
      scanf("%d", &end);
      problems += end - start + 1;
      char x = getchar();
    
      if (x == ';') continue;
      else break;
    } else if (c == ';') {
      problems += 1;
      continue;
    } else {
      problems += 1;
      break;
    }
  }
  printf("%d\n", problems);
}