n = int(input())
xy = [tuple(map(int,input().split())) for _ in range(n)]
s = set(xy); c = 0
for i in range(n-2):
    xi,yi = xy[i]
    for j in range(i+1,n-1):
        xj,yj = xy[j]
        for k in range(j+1,n):
            xk,yk = xy[k]
            t = {xy[i],xy[j],xy[k]}
            if (xi-xk)**2+(yi-yk)**2==(xj-xk)**2+(yj-yk)**2 and (xi+xj-xk,yi+yj-yk) in s and (xi+xj-xk,yi+yj-yk) not in t: c += 1
            if (xj-xi)**2+(yj-yi)**2==(xk-xi)**2+(yk-yi)**2 and (xj+xk-xi,yj+yk-yi) in s and (xj+xk-xi,yj+yk-yi) not in t: c += 1
            if (xk-xj)**2+(yk-yj)**2==(xi-xj)**2+(yi-yj)**2 and (xk+xi-xj,yk+yi-yj) in s and (xk+xi-xj,yk+yi-yj) not in t: c += 1
print(c//4)