View Compilation Error

0_0_16999251_26491.cpp: In function 'int main()':
0_0_16999251_26491.cpp:145:51: error: unable to find numeric literal operator 'operator""a'
                             dp[t+1][x^flag]=(dp[t+1a][x^flag]+dp[t][x])%MOD;
                                                   ^
0_0_16999251_26491.cpp:145:51: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes