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| #include <bits/stdc++.h>
#pragma optimization_level 3 #pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3") #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx") #pragma GCC optimize("Ofast") #pragma GCC target("avx,avx2,fma") #pragma GCC optimization ("unroll-loops")
struct PairHash {inline std::size_t operator()(const std::pair<int,int> & v) const {return v.first*31+v.second;}};
#define MAX_N 151515 #define INF 987654321 #define EPS 1e-9 #define ll long long #define pll pair<ll, ll> #define vpll vector<pll> #define vall3 vector<array<ll,3>> #define all3 array<ll,3> #define all5 array<ll,5> #define vall5 vector<all5> #define vll vector<ll> #define vi vector<int> #define vs vector<string> #define usll unordered_set<ll> #define uspll unordered_set<pll, PairHash> #define vvs vector<vs> #define vvll vector<vll> #define all(a) begin(a), end(a) #define rall(a) rbegin(a), rend(a)
using namespace std;
ll solve(ll n, ll A, ll B) { if(A == 1 or B == 1) return 0; ll now = 1, a = A, b = B; ll res = 0; while(now <= n) { ll mi = min({a, b, n + 1});
res += (mi - now) * (now + mi - 1) / 2;
now = mi + 1; if(a == mi) a += A; if(b == mi) b += B; } return res; }
int main() { ios_base::sync_with_stdio(0); cin.tie(0); ll tc = 1; for(ll i = 1; i <= tc; i++) { ll n, a, b; cin>>n>>a>>b; cout<<solve(n,a,b)<<endl; } return 0; }
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