View Compilation Error

0_0_22447957_32253.cpp: In function 'int main()':
0_0_22447957_32253.cpp:35:23: error: 'a' was not declared in this scope
   while(scanf("%d%d",&a,&b)!=EOF)
                       ^
0_0_22447957_32253.cpp:35:26: error: 'b' was not declared in this scope
   while(scanf("%d%d",&a,&b)!=EOF)
                          ^