$K^{0}_{s}$ and $\Lambda$ Analysis in Proton-Carbon Collisions at $30$ GeV/$c$

NA61/SHINE is a large hadron spectrometer located at North Area of CERN-SPS. There are 3 physics goals persuaded by NA61: search for the critical point of strongly interacting matter, hadron production measurement for the T2K neutrino experiment in Japan and measurements for the Piere-Augere and KASCADE cosmic ray observatories. After short introduction of the experiment I will present my contribution. My task was to calculate $K^{0}_{s}$ and $\Lambda$ yields in proton-carbon interactions. The results aim to improve predictions of the neutrino flux in the T2K experiment. The data were recorded in year 2009 using a secondary-proton beam of $31$ GeV/$c$ momentum scattered off a graphite target. To determine the inclusive production cross-section for hadrons the thin ($0.04\: \lambda_{l}$) target was exploited. Results of this measurement will be used in the T2K beam simulation program to constrain parameters of the neutrino flux.