I was solving [This](https://codeforces.me/problemset/problem/1477/B) problem and submitted [submission:106080441].I am getting runtime errors on test 4.The codeforces diagnoser says it is because it is of integer overflow I changed everything to long long but it gives me again the same error.Can anyone say Whats wrong with my code please?Thanks.↵
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Edit:Ok I got it I should have checked lx<a.size();
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Edit:Ok I got it I should have checked lx<a.size();