When a specimen of M25 concrete is loaded to a stress level of 12.5 MPa, a strain of 500 × 10^-6 is recorded. If this load is allowed to stand for a long time, the strain increases to 1000 × 10^-6. In accordance with the provisions of IS:456-2000, considering the long-term effects, the effective modulus of elasticity of the concrete (in MPa) is _______.