```
public class Solution {
public int removeDuplicates(int[] nums) {
int shiftCount = 0;
for(int i=0; i<nums.length-1; i++) {
if(nums[i]==nums[i+1]) {
shiftCount++;
} else if (shiftCount!=0) {
nums[i+1-shiftCount] = nums[i+1];
}
}
return nums.length-shiftCount;
}
}
```