'use strict'

function main(input) {
    const inputs = input.trim().split(/\n/)
    const len = ~~inputs[0]
    if (inputs[1].length <= len) {
        console.log(inputs[1])
    } else {
        console.log(`${inputs[1].slice(0, len)}...`)
    }
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'))
