View Compilation Error

0_0_39850753_19645.cpp: In function 'int main()':
0_0_39850753_19645.cpp:3:24: error: 'a' was not declared in this scope
    3 |    while(scanf("%d%d",&a,&b)!=EOF){
      |                        ^
0_0_39850753_19645.cpp:3:27: error: 'b' was not declared in this scope
    3 |    while(scanf("%d%d",&a,&b)!=EOF){
      |                           ^