text: const readline = require('readline');
  const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
  });
  
  let input = [];
  
  rl.on('line', function (line) {
      input = line.split(' ').map((el) => parseInt(el));
  }).on('close', function () {
      console.log(input[0] - input[1]);
      process.exit();
  });
  