  We consider a linear skew product with the full shift in the base and nonzero
Lyapunov exponent in the fiber. We provide a sharp estimate for the precision
of shadowing for a typical pseudotrajectory of finite length. This result
indicates that the high-dimensional analog of Hammel-Yorke-Grebogi's conjecture
concerning the interval of shadowability for a typical pseudotrajectory is not
correct. The main technique is reduction of the shadowing problem to the ruin
problem for a simple random walk.
