func_code_string: #include <bits/stdc++.h>   #pragma GCC optimize( Ofast )   #pragma GCC target( sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma )   #pragma GCC optimize( unroll-loops )   using namespace std;   long long int MOD = 998244353;   double eps = 1e-12;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     long long int k, n, w, product = 0;     cin >> k >> n >> w;     for (int i = 1; i <= w; i++) {       product += (i * k);     }     long long int res = product - n;     if (res <= 0)       cout <<  0  << endl;     else       cout << res << endl;     return 0;   }   