Pares de numeros - Obi 2020

#https://olimpiada.ic.unicamp.br/static/extras/obi2019/provas/ProvaOBI2019_f3pj.pdf
N,I,F = [int(i) for i in input().split()]
V = [int(i) for i in input().split()]
quant = 0
V = sorted(V)

for a in range(N):
    for b in range(a+1,N):
        if (V[a]+V[b]) >= I and (V[a]+V[b]) <= F:
            quant += 1

print(quant)