function main(input) {
  const args = input.split('\n');
  const [N, K] = args[0].split(' ').map((n) => parseInt(n, 10));
  const sunukes = new Array(N).fill(false);

  for (let i = 2; i <= K * 2; i += 2) {
    args[i].split(' ').map((n) => parseInt(n, 10)).map((A) => {
      sunukes[A] = true;
    });
  }

  console.log(sunukes.reduce((num, sunuke) =>
    sunuke ? num : num + 1
  ));
}

main(require('fs').readFileSync('/dev/stdin', 'utf8'));
