View Compilation Error

0_0_16269515_6540.cpp: In function 'int main()':
0_0_16269515_6540.cpp:40:20: error: 'a' was not declared in this scope
    if(x>maxx) maxx=a;
                    ^
0_0_16269515_6540.cpp:41:20: error: 'b' was not declared in this scope
    if(y>maxx) maxx=b;
                    ^