#include <inttypes.h>
#include <limits.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

int main(){
 char *ones[9] = { "one", "two", "three", "four", "five", "six", "seven",
  "eight", "nine" };
 char *teens[10] = { "ten", "eleven", "twelve", "thirteen", "fourteen",
  "fifteen", "sixteen", "seventeen", "eighteen", "nineteen" };
 char *tens[9] = { "ten", "twenty", "thirty", "forty", "fifty", "sixty",
  "seventy", "eighty", "ninety" };
 char *rest[6] = { "thousand", "million", "billion", "trillion", "quadrillion",
  "quintillion" };
 size_t len;
 printf("enter integer: ");
 char *line = fgetln(stdin, &len);
 line[len] = 0;
 intmax_t num = strtoimax(line, NULL, 0);
 if(!num){
  puts("zero.");
  return 0;
 }
 if(num < 0){
  num *= -1;
  printf("negative ");
 }
 int parts[7];
 int last = 0;
 for(int i = 0; i < 7; ++i){
  parts[i] = num % 1000;
  if(!parts[i] && last == i) ++last;
  num /= 1000;
 }
 for(int i = 6; i >= 0; --i){
  if(parts[i]){
   int n = parts[i];
   int o = n % 10;
   int t = (n / 10) % 10;
   int h = (n / 100) % 10;
   if(h) printf("%s %s%s", ones[h - 1], "hundred", t || o ? " " : "");
   switch(t){
    case 0:
     if(o) printf("%s", ones[o - 1]);
     break;
    case 1:
     printf("%s", teens[o]);
     break;
    default:
     if(o) printf( "%s-%s", tens[t - 1], ones[o - 1]);
     else printf("%s", tens[t - 1]);
   }
   if(i) printf(" %s%s", rest[i - 1], i == last ? "" : " ");
  }
 }
 puts(".");
 return 0;
}