BALKAN-SL 2013 C3

The square $ABCD$ is divided into $n^2$ equal small (elementary) squares by parallel lines to its sides, (see the figure for the case $n = 4$ ). A spider starts from point $A$ and moving only to the right and up tries to arrive at point $C$ . Every " movement" of the spider consists of: " $k$ steps to the right and $m$ steps up" or " $m$ steps to the right and $k$ steps up" (which can be performed in any way). The spider first makes $l$ "movements" and in then, moves to the right or up without any restriction. If $n = m \cdot l$ , find all possible ways the spider can approach the point $C$ , where $n, m, k, l$ are positive integers with $k < m$ .