function main(input) {
  const args = input.split('\n');
  
  const N = args[0];
  nums = args.slice(1, args.length).map(n => parseInt(n, 10));
  
   console.log(nums.filter((n, i) => nums.indexOf(n) === i).length);
}

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