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import sys
def main():
    n = int(sys.stdin.readline())
    points = []
    for _ in range(n):
        x, y = map(int, sys.stdin.readline().split())
        points.append((x, y))
    
    result = 0
    for i in range(n):
        xi, yi = points[i]
        for j in range(i + 1, n):
            xj, yj = points[j]
            for k in range(j + 1, n):
                xk, yk = points[k]
                # ?????
                det = (xj - xi) * (yk - yi) - (xk - xi) * (yj - yi)
                if det != 0:
                    result += 1
    print(result)
if __name__ == "__main__":
    main()

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