What is the probability that in a room filled with 23 people, at least one pair of people has the same birthday?

```
(define N 23)
(define (two-birthdays-match?)
(rejection-query
(define birthday
(mem (lambda (i) (+ (sample-integer 365) 1))))
(define (pair-equal i j)
(if (> i N)
false
(if (> j N)
(pair-equal (+ i 1) (+ i 2))
(if (= (birthday i) (birthday j))
true
(pair-equal i (+ j 1))))))
(pair-equal 1 2)
#t))
(hist (repeat 1000 two-birthdays-match?))
```

References: