static long countDolphin(int n, int m, int[] birthYear, int x) { int len = birthYear.length; long sum = 0; if(x>m){sum = 0;}else {sum =n;} for(int i = 0;i<len;i++){ if(x-birthYear[i]>=0){ sum = sum +countDolphin(n,m,birthYear,x-birthYear[i]); }} return sum; }