I am trying to find the parameters p0 and p1 and am getting the error ‘PARSER EXPECTED: ’ on the model equation with y ~. Any advice on why?

```
data {
int<lower=0> N;
vector[N] y;
vector[N] d;
}
parameters {
real p0;
real<lower=p0> p1;
}
model {
p0 ~ beta(0.5,0.5);
p1 ~ beta(0.5,0.5);
y ~ 1/(1+exp(-logit(p0)-(logit(p1)-logit(p0))*d));
}
```