View Compilation Error

0_0_39515218_11420.cpp: In function 'int main()':
0_0_39515218_11420.cpp:53:48: error: expected ';' before 'for'
   53 |         cin>>n, ans = n * (n - 1) * (n - 2) / 6
      |                                                ^
      |                                                ;
   54 |         for(int i = 1;i <= n;i = -~i) cin>>sum[i].f, id[i] = i;
      |         ~~~                                     
0_0_39515218_11420.cpp:54:23: error: 'i' was not declared in this scope
   54 |         for(int i = 1;i <= n;i = -~i) cin>>sum[i].f, id[i] = i;
      |                       ^