Page Calculator

const input = [
    ['Telerik', 'Java', 'CSS', 'JavaScript', 'PHP', 'HTML', 'CSS', 'Spring', 'Angular'],
    '2',
    'CSS'
];

const print = this.print || console.log;
const gets = this.gets || ((arr, index) => () => arr[index++])(input, 0);

const arr = gets();
const words = +gets();
const keyword = gets();
let index = -1;

for (let i = 0; i < arr.length; i++) {
    if (arr[i] == keyword) {
        index = i;
    }
}

if (index > -1) {
    let page = Math.ceil((index + 1) / words);
    print(page);
} else {
    print(-1);
}