View Compilation Error

0_0_33619010_5859.cpp:16:11: error: conflicting declaration 'const int mod'
 const int mod=1e9+7;
           ^
0_0_33619010_5859.cpp:9:5: note: previous declaration as 'int mod'
 int mod=1e9+7;
     ^
0_0_33619010_5859.cpp:18:5: error: redefinition of 'int n'
 int n,m,cas,k,cnt,tot;
     ^
0_0_33619010_5859.cpp:5:5: note: 'int n' previously declared here
 int n,m;
     ^
0_0_33619010_5859.cpp:18:7: error: redefinition of 'int m'
 int n,m,cas,k,cnt,tot;
       ^
0_0_33619010_5859.cpp:5:7: note: 'int m' previously declared here
 int n,m;
       ^
0_0_33619010_5859.cpp: In function 'int main()':
0_0_33619010_5859.cpp:104:5: error: redefinition of 'int main()'
 int main()
     ^
0_0_33619010_5859.cpp:60:5: note: 'int main()' previously defined here
 int main()
     ^