X and Two Groups

Tumut, the best programmer in his village Applidz, invented a problem and decided to share it with you: You are given two integer sequences $S_1, S_2, \dots, S_N$ and $T_1, T_2, \dots, T_M$ and an integer $x$. You are allowed to perform the following operation any number of times: - choose an element of $S$ and an element of $T$ (let's denote them by $S_i$ and $T_j$ respectively) - decrease both