\gamma_{1}(t)=1-e^{it} ,\gamma_{2}(t)=3+e^{-it} \\ pa \int_{\gamma} f(z)dz=\int_{0}^{\pi}f(\gamma_1(t))\gamma_{1}'(t) dt+\int_{\pi}^{2\pi}f(\gamma_2(t))\gamma_{2}'(t) dt?