Finding Complexity of loops

How to find complexity of this loop

Program 1:

for(i=1;i<=n;i++)
{
for(j=n/3;j<=2n;j+=n/3)
{
 x=x+1;
}
}

I've solved question like this

Program 2:

for(i=1;i<=n;i++)
{
for(j=1;j<=n;j++)
{
 x=x+1;
}
}

here time complexity of above code will be $O(n^2)$ But how to find time complexity of programs like Program 1