View Compilation Error

0_0_13331174_14087.cpp: In function 'int main()':
0_0_13331174_14087.cpp:5:13: error: redeclaration of 'long int a'
  long m,n,a,a,i;
             ^
0_0_13331174_14087.cpp:5:11: note: 'long int a' previously declared here
  long m,n,a,a,i;
           ^