process.stdin.resume();
process.stdin.setEncoding('utf8');
 
// your code goes here
var readline = require("readline")
 
function uniqFilter() {
    var seen = {}
    return function(xs) {
        return xs.filter(function(x, _, _) {
            return (x in seen) ? false : (seen[x] = true)
        })
    }
}
function main() {
    var uniq = uniqFilter()
    var rl = readline.createInterface({input:  process.stdin,
                                       output: process.stdout})
    rl.setPrompt('')
    rl.on('line', function(line) {
        var words = line.match(/\S+/g) || []
        uniq(words).forEach(function(x, _, _) { console.log(x) })
    })
}
main()
 

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