View Compilation Error

0_0_17935027_16549.cpp: In function 'LL get(int, int)':
0_0_17935027_16549.cpp:51:8: error: 'a' was not declared in this scope
     if(a+2*b!=y||2*a+b!=x) return 0;
        ^
0_0_17935027_16549.cpp:51:12: error: 'b' was not declared in this scope
     if(a+2*b!=y||2*a+b!=x) return 0;
            ^