View Compilation Error

0_0_22265756_16446.cpp: In function 'int main()':
0_0_22265756_16446.cpp:6:21: error: 'a' was not declared in this scope
 while(scanf("%d%d",&a,&b) != EOF)
                     ^
0_0_22265756_16446.cpp:6:24: error: 'b' was not declared in this scope
 while(scanf("%d%d",&a,&b) != EOF)
                        ^