View Compilation Error

0_0_26489708_13614.cpp: In function 'int main()':
0_0_26489708_13614.cpp:5:23: error: 'a' was not declared in this scope
     while(scanf("%d",&a)!=EOF)
                       ^
0_0_26489708_13614.cpp:12:25: error: 'b' was not declared in this scope
             scanf("%d",&b);
                         ^