# Restrictions on 2SLS problems and SHAZAM

**A SHAZAM User asked:**

I had some problems running Shazam as follows.

C, I, Y are three endogenous variables. G and R are two exogenous variables.

There are three equations, two with constants and coefficients, but one is like this:

```
Y=C+I+G
```

I wonder if I can still use the 2SLS function and so I wrote the code like this:

```
2SLS C Y (R G) / DN
2SLS I R (R G) / DN
2SLS Y C I G (R G) / RESTRICT
RESTRICT C=1
RESTRICT I=1
RESTRICT G=1
END
```

But, it doesn't work. The results are different to my analytical results, which I'm pretty sure are correct.

Can you please help me with this.