foo.cpp:8:1: error: 'll' does not name a type
 ll dp[2][M][N];
 ^
foo.cpp: In function 'int main()':
foo.cpp:19:5: error: 'dp' was not declared in this scope
     dp[k&1][i][j]=0;
     ^
foo.cpp:28:18: warning: suggest parentheses around arithmetic in operand of '^' [-Wparentheses]
     sum=(sum+dp[k&1^1][i-1][j])%mod;
                  ^
foo.cpp:34:12: error: 'dp' was not declared in this scope
   ans=(ans+dp[K&1][m][i])%mod;
            ^