function main(input) {
  const a1 = parseInt(input.split(" ")[0], 10);
  const a2 = parseInt(input.split(" ")[1], 10);
  const a3 = parseInt(input.split(" ")[2], 10);
  console.log(a3-a1);
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));