C++ - Sizeof() strikes again

Question

In the following code, I understand n1 is 9, but WHY n2 is 2?

int mas[9] = {2, 6, 3, 9, 1, 0, 5, 8, 4};
int* p = new int[9];
for(int i = 0; i < 9; ++i){
p[i] = mas[i];
}
int n1 = sizeof(mas)/sizeof(*mas);
int n2 = sizeof(p)/sizeof(*p);
cout << n1 << n2;