View Compilation Error

0_0_34911125_921.cpp: In function 'int main()':
0_0_34911125_921.cpp:3:22: error: 'a' was not declared in this scope
  while(scanf("%d%d",&a,&b)!=EOF){
                      ^
0_0_34911125_921.cpp:3:25: error: 'b' was not declared in this scope
  while(scanf("%d%d",&a,&b)!=EOF){
                         ^