var lines = []; var counter = 0; var reader = require('readline').createInterface({ input: process.stdin, output: process.stdout }); reader.on('line', function (line) { counter += 1; lines.push(line); if( counter == 1 ) { main(); process.exit(0); } }); process.stdin.on('end', function () { //do something }); function main(){ ents = []; lines.map(function(x){ var num = parseInt(x); if ( num == 0 ) { console.log(1); } else { console.log(0); } }); }