View Compilation Error

0_0_27386347_31193.cpp: In function 'int main()':
0_0_27386347_31193.cpp:5:22: error: 'a' was not declared in this scope
 while(scanf("%d %d",&a,&b)!=EOF){
                      ^
0_0_27386347_31193.cpp:5:25: error: 'b' was not declared in this scope
 while(scanf("%d %d",&a,&b)!=EOF){
                         ^