View Compilation Error

0_0_14022851_303.cpp: In function 'int main()':
0_0_14022851_303.cpp:57:24: error: 'a' was not declared in this scope
         scanf("%d%d", &a, &b);
                        ^
0_0_14022851_303.cpp:57:28: error: 'b' was not declared in this scope
         scanf("%d%d", &a, &b);
                            ^