const fs = require('fs') const readline = require('readline'); const readInterface = readline.createInterface({ input: fs.createReadStream('input'), console: false }); let re = /^(\d+)-(\d+) (\w+): (\w+)$/i let valid = 0; readInterface.on('line', function(line) { let result = re.exec(line); if (result == null) { return; } let pos1 = Number(result[1]) - 1; let pos2 = Number(result[2]) - 1; let match = result[3]; let pass = result[4]; if ((pass[pos1] == match && pass[pos2] != match) || (pass[pos1] != match && pass[pos2] == match)) { valid++; }; }); readInterface.on('close', function(line) { console.log(valid); });