View Compilation Error

0_0_33652510_8641.cpp:32:13: error: conflicting declaration 'int N'
 int n,m,s,t,N;
             ^
0_0_33652510_8641.cpp:28:11: note: previous declaration as 'const int N'
 const int N = 1e5 + 5;
           ^
0_0_33652510_8641.cpp: In function 'int main()':
0_0_33652510_8641.cpp:101:22: error: assignment of read-only variable 'N'
         s = 0, t = N = 2 * n + 1;
                      ^