In this short article, we find an explicit formula for Maslov index of Whitney $n$-gons joining intersections points of $n$ half-dimensional tori in the symmetric product of a surface. The method also yields a formula for the intersection number of such an $n$-gon with the fat diagonal in the symmetric product.
"Maslov index formulas for Whitney $n$-gons." J. Symplectic Geom. 9 (2) 251 - 270, June 2011.