const [A, B] = require('fs').readFileSync('/dev/stdin', 'utf8')
  .split(/\s/)
  .map(v => +v);

console.log(3 -
  [23, 24, 25]
  .filter(v => [...Array(B - A + 1).keys()]
    .map(v => v + A)
    .includes(v))
  .length);