View Compilation Error

0_0_18941073_9054.cpp: In function 'int solve()':
0_0_18941073_9054.cpp:53:31: error: 'a' was not declared in this scope
         num[1] = (s[1]-'0') - a;
                               ^
0_0_18941073_9054.cpp:54:33: error: 'b' was not declared in this scope
         res = (res + get_num(a, b)) % mod;
                                 ^