title: Number of digits for N**K
body: <p>For given integers N and K (1 &lt;= N, K &lt;= 2000000000) you have to find the number of digits of N^K.</p>
  
  <p>Is there any formula or something ? Because I tried solving it by simply powering N**K but it's not working for large values and the program simply freezes because of the calculations. I am looking for some fast way maybe some math formula like I said before. </p>