#include <bits/stdc++.h>
int main() {
  int a, b, c, i, count;
  scanf("%d %d %d", &a, &b, &c);
  count = 0;
  for (i = a + 1; i <= b; i++) {
    if (80 % i == 0) {
      count = count + 1;
    }
  }
  printf("%d\n", count);
  return (0);
}
