How can I write a contour integration in Mathematics Stack Exchange? [duplicate]

How can I write a contour integration (from complex analysis) in Mathematics Stack Exchange?

I have many questions relating to contour integration in complex analysis, but I don't know how to write a contour integration. There is no 'contour' option on my keyboard.

If anybody helps me, I would be very thankful.

marked as duplicate by Simply Beautiful Art, José Carlos Santos, Shailesh, Watson, yoknapatawphaAug 26 '17 at 19:22

• $$\int_\gamma f(z)dz, \qquad \int_{|z| = 1} f(z)dz, \qquad \int_{0 \to 1 \to 1+i \to i \to 0} f(z)dz$$ – reuns Aug 18 '17 at 15:37
• \oint (in math mode) gives $\oint$. – Andrés E. Caicedo Aug 18 '17 at 21:25