A steel bar made of AISI 4340 steel (of = 1758 MPa and b = -0.098) is subjected to uniaxial cyclic loading of variable amplitude at zero mean stress. There are three blocks of loading at 3 different amplitudes. The first block has a = 600 MPa for 2000 cycles; the second block has = 550 MPa for 10,000 cycles. The third block has = 750 MPa. Using Miner's rule, estimate the number of cycles that can be applied in the third block before fatigue failure is expected.