1
let n = +gets();
const factorial = (n) => {
    if (n<2) return 1
    return n * factorial(n-1);
}
print(factorial(n))

2
const numberOfBunnies = +gets();
const numberOfEars = (bunnies) => {
    if (bunnies === 0) return 0
    return 2 + numberOfEars(bunnies-1)
}
print(numberOfEars(numberOfBunnies))

4
const numberOfBunnies = +gets();
const numberOfEars = (bunnies) => {
    if (bunnies === 0)return 0;
    return bunnies%2===0 ? 3 + numberOfEars(bunnies-1): 2 + numberOfEars(bunnies-1);
}
print(numberOfEars(numberOfBunnies))

5
const n = +gets();
const pyramide = (n)=>{
    if(n === 0) return 0;
    return n+ pyramide(n-1);
}
print(pyramide(n))

6
const num = +gets();
const sum = (n) => {
    if(n === 0) return 0;
    return n%10 + sum(Math.trunc(n/10))
}
print(sum(num))

7
let num = +gets();
let count = 0;
function sum(n) {
  if (n === 0) return 0;
  let first = (n % 10);
  if (first === 7) count++;
  sum(Math.trunc(n / 10));
  return count;
};
print(sum(num));

8
let num = +gets();
let count = 0;
function sum(n) {
  if (n === 0) return 0;
  let first = (n % 10);
  let second = (Math.trunc(n / 10)) % 10;
  if (first === 8 ) {
      if(first === second){
          count+=2;
      }else {
          count++
      }
  }
  sum(Math.trunc(n / 10))
  return count;
};
print(sum(num));

9
let num = +gets();
let pows = +gets();
const pow = (n, p) => {
    if(p === 0) return 1;
    return n* pow(n, p-1);
}
print(pow(num, pows))

10
let string = gets();
let count = 0;
const findX = (string) => {
    if(!string.length) return;
    if(string[0] === 'x') count++;
    const newString = string.slice(1);
    findX(newString)
    return count
}
print(findX(string))

11
let string = gets();
let count = 0;
const search = (string) => {
    if(!string.length) return;
    if (string[0] === 'h' && string[1] === 'i') count++
    const newString = string.slice(1);
    search(newString)
    return count
}
print(search(string))

12
let string = gets();
let final = ''
let newString = '';
const search = (string) => {
    if(!string.length) return;
    if(string[0] === 'p' && string[1] === 'i') {
        final += '3.14'
        newString = string.slice(2);
    } else {
        final += string[0];
        newString = string.slice(1)
    }
    search(newString)
    return final
}
print(search(string))

13
const arrays = gets().split(',').map(Number);
const index = +gets();
const searchForSix = (arrays, index) => {
    if ( arrays[index] === 6) return true
    if ( index === arrays.length) return false;
    return searchForSix(arrays,index+1)
}
print(searchForSix(arrays, index))

14
const arrays = gets().split(',').map(Number);
const index = +gets();
let count = 0;
const searchForSix = (arrays, index) => {
    if ( index === arrays.length) return;
    if ( arrays[index] === 11) count++
    searchForSix(arrays,index+1)
    return count
}

15
const arrays = gets().split(',').map(Number);
const index = +gets();
const something = ( array , index) => {
    if ( index === array.length) return false;
    if (array[index]*10 === array[index+1]) return true;
    return something(array, index+1)
}
print(something(arrays, index))