  We evaluate quasi-classically the Ramond partition function of Euclidean D=10
U(N) super-Yang--Mills theory reduced to a two-dimensional torus. The result
can be interpreted in terms of free strings wrapping the space-time torus, as
expected from the point of view of Matrix string theory. We demonstrate that,
when extrapolated to the ultraviolet limit (small area of the torus), the
quasi-classical expressions reproduce exactly the recently obtained expression
for the partition of the completely reduced SYM theory, including the overall
numerical factor. This is an evidence that our quasi-classical calculation
might be exact.
