View Compilation Error

0_0_25596436_28184.cpp: In function 'int main()':
0_0_25596436_28184.cpp:35:6: error: expected ';' before 'ans'
   ll ans = 0;
      ^
0_0_25596436_28184.cpp:50:7: error: 'ans' was not declared in this scope
       ans++, S.pop();
       ^
0_0_25596436_28184.cpp:76:4: error: 'ans' was not declared in this scope
    ans += a[i].l;
    ^
0_0_25596436_28184.cpp:80:20: error: 'ans' was not declared in this scope
   printf("%lld\n", ans * 2);
                    ^