 Complete the following phrase:  The first experimental T-60ies were produced by July 1941, but serial production did not begin until the autumn of the same year. However, once priority was given to it at the GAZ, at the expense of truck production, hundreds could be built monthly, total production in 1941 alone reaching more than 1360 units, 1177 of them built at the Nizhny Novgorod factory. The tanks participated in the 