View Compilation Error

0_0_22118017_4696.cpp: In function 'int main()':
0_0_22118017_4696.cpp:6:25: error: 'a' was not declared in this scope
     while(scanf("%d%d",&a,&b)!=EOF)
                         ^
0_0_22118017_4696.cpp:6:28: error: 'b' was not declared in this scope
     while(scanf("%d%d",&a,&b)!=EOF)
                            ^