#![allow(non_snake_case, unused_imports)]
use std::io::{self, prelude::*};
use std::str;

fn gcd(a: usize, b: usize) -> usize {
    if a < b {
        return gcd(b, a);
    }

    if b == 0 {
        return a;
    } else {
        return gcd(b, a % b);
    }
}

fn main() {
    let (stdin, stdout) = (io::stdin(), io::stdout());
    let mut scan = Scanner::new(stdin.lock());
    let mut out = io::BufWriter::new(stdout.lock());

    macro_rules! input {
        ($T: ty) => {
            scan.token::<$T>()
        };
    }

    let N = input!(usize);

    let mut XY = vec![];

    for _ in 0..N {
        let (x, y) = (input!(isize), input!(isize));
        XY.push((x, y));
    }

    let mut ans = 0;

    for i in 0..N {
        let (x1, y1) = XY[i];

        let mut S = std::collections::BTreeSet::new();
        for j in 0..N {
            if i == j {
                continue;
            }

            let (x2, y2) = XY[j];

            let (mut dx, mut dy) = (x1 - x2, y1 - y2);
            let (gx, gy) = (dx.abs() as usize, dy.abs() as usize);
            let g = gcd(gx, gy) as isize;
            dx /= g;
            dy /= g;

            if S.contains(&(dx, dy)) {
                ans += 1;
                break;
            }

            S.insert((dx, dy));
        }
    }

    writeln!(out, "{}", ans);
}

struct Scanner<R> {
    reader: R,
    buf_str: Vec<u8>,
    buf_iter: str::SplitWhitespace<'static>,
}
impl<R: BufRead> Scanner<R> {
    fn new(reader: R) -> Self {
        Self {
            reader,
            buf_str: vec![],
            buf_iter: "".split_whitespace(),
        }
    }
    fn token<T: str::FromStr>(&mut self) -> T {
        loop {
            if let Some(token) = self.buf_iter.next() {
                return token.parse().ok().expect("Failed parse");
            }
            self.buf_str.clear();
            self.reader
                .read_until(b'\n', &mut self.buf_str)
                .expect("Failed read");
            self.buf_iter = unsafe {
                let slice = str::from_utf8_unchecked(&self.buf_str);
                std::mem::transmute(slice.split_whitespace())
            }
        }
    }
}