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#include<iostream>#include<vector>#include<string>#include<cmath>using namespace std;int main(){freopen("in.txt","r",stdin);int a,n;cin>>a>>n;vector<int> sum(n,0);for(int i=0;i<n;i++){sum[i]=(n-i)*a;}int carry=0;for(int i=0;i<n;i++){sum[i]+=carry;carry=sum[i]/10;sum[i]=sum[i]%10;}while(carry>0){sum.push_back(carry%10);carry=carry/10;}if(sum.empty()){cout<<0<<endl;return 0;}for(vector<int>::reverse_iterator itr=sum.rbegin();itr!=sum.rend();++itr){cout<<*itr;}cout<<endl;}