Why I am getting stackoverflow in this problem?

Question

This is my Program for finding the power of number using recursion but when I am trying to submit I am getting an error The link for this problem is here

long power(int N,int R)
    {
        
       if(R==0)
       {
           return 1;
       }
       if(N==0)
       {
         return 0;  
       }
      return (N*power(N,R-1)%1000000007);              
}