View Compilation Error

0_0_14954251_7375.cpp: In function 'int main()':
0_0_14954251_7375.cpp:125:5: error: redefinition of 'int main()'
 int main()
     ^
0_0_14954251_7375.cpp:49:5: note: 'int main()' previously defined here
 int main()
     ^
0_0_14954251_7375.cpp:135:10: error: 'a' was not declared in this scope
    readd(a[++n].x);a[n].v=1;
          ^
0_0_14954251_7375.cpp:138:8: error: 'a' was not declared in this scope
   sort(a+1,a+n+1);
        ^
0_0_14954251_7375.cpp:144:35: error: 'add' was not declared in this scope
    add(ans,Z-b[g-sum]*(a[i].x-p)%Z);
                                   ^