View Compilation Error

0_0_18024169_17621.cpp: In function 'int main()':
0_0_18024169_17621.cpp:91:57: error: 'x' was not declared in this scope
                     dp[i][j-1] = (dp[i][j-1] + dp[i][j]*x%MOD)%MOD;
                                                         ^