ok so I'm kinda new to java and I'm trying to make a class which will be able to ask the user to input a 12 digit long upc code, check to make sure its a valid code, and then display if it is or not. I've got quite a few errors with the current program that I have and I can't seem to figure it out. This is the code that I have so far: 

```
public class Upc {
    private long upc;

    public Upc(long upcs) {
        upc = upcs;
    }

    public long getUpc() {

        int m = (n2 + n4 + n6 + n8 + n10);
        long n = (n1 + n3 + n5 + n7 + n9 + n11);
        long r = (10 - (m + 3 * n) % 10);

        long n12 = (int) (upc % 10);
        upc /= 10;
        long n11 = (int) (upc % 10);
        upc /= 10;
        long n10 = (int) (upc % 10);
        upc /= 10;
        long n9 = (int) (upc % 10);
        upc /= 10;
        long n8 = (int) (upc % 10);
        upc /= 10;
        long n7 = (int) (upc % 10);
        upc /= 10;
        long n6 = (int) (upc % 10);
        upc /= 10;
        long n5 = (int) (upc % 10);
        upc /= 10;
        long n4 = (int) (upc % 10);
        upc /= 10;
        long n3 = (int) (upc % 10);
        upc /= 10;
        long n2 = (int) (upc % 10);
        upc /= 10;
        long n1 = (int) (upc % 10);

        if (r == n12) {
            return (upc + " is a feasible UPC code");
        } else {
            return (upc + " is an invalid UPC code");
        }
    }
}

```

and my errors are as follows:

```
13 errors found:
File: C:\Users\Andrew\Downloads\Upc.java  [line: 10]
Error: n2 cannot be resolved to a variable
File: C:\Users\Andrew\Downloads\Upc.java  [line: 10]
Error: n4 cannot be resolved to a variable
File: C:\Users\Andrew\Downloads\Upc.java  [line: 10]
Error: n6 cannot be resolved to a variable
File: C:\Users\Andrew\Downloads\Upc.java  [line: 10]
Error: n8 cannot be resolved to a variable
File: C:\Users\Andrew\Downloads\Upc.java  [line: 10]
Error: n10 cannot be resolved to a variable
File: C:\Users\Andrew\Downloads\Upc.java  [line: 11]
Error: n1 cannot be resolved to a variable
File: C:\Users\Andrew\Downloads\Upc.java  [line: 11]
Error: n3 cannot be resolved to a variable
File: C:\Users\Andrew\Downloads\Upc.java  [line: 11]
Error: n5 cannot be resolved to a variable
File: C:\Users\Andrew\Downloads\Upc.java  [line: 11]
Error: n7 cannot be resolved to a variable
File: C:\Users\Andrew\Downloads\Upc.java  [line: 11]
Error: n9 cannot be resolved to a variable
File: C:\Users\Andrew\Downloads\Upc.java  [line: 11]
Error: n11 cannot be resolved to a variable
File: C:\Users\Andrew\Downloads\Upc.java  [line: 39]
Error: Type mismatch: cannot convert from java.lang.String to long
File: C:\Users\Andrew\Downloads\Upc.java  [line: 42]
Error: Type mismatch: cannot convert from java.lang.String to long

```

I feel like fixing one or two things will eliminate alot of this, can anyone help me?