/*#include // cout, endl, cin #include // string, to_string, stoi #include // vector #include // min, max, swap, sort, reverse, lower_bound, upper_bound #include // pair, make_pair #include // tuple, make_tuple #include // int64_t, int*_t #include // printf #include // map #include // queue, priority_queue #include // set #include // stack #include // deque #include // unordered_map #include // unordered_set #include // bitset #include // isupper, islower, isdigit, toupper, tolower #include //fixed,setprecision #include //INT_MAX #include //M_PI*/ #include using namespace std; #include using namespace atcoder; //using mint = modint1000000007; using mint = modint998244353; template bool chmax(T &u, const T z) { if (u < z) {u = z; return true;} else return false; } template bool chmin(T &u, const T z) { if (u > z) {u = z; return true;} else return false; } #define ll long long #define rep(i, n) for (ll i = 0; i < (ll)(n); i++) typedef pair P; ll gcd(ll x, ll y) { return y ? gcd(y, x % y) : x; } ll lcm(ll a, ll b){return a * b / gcd(a, b);} int main(){ ll a,b,n,m; cin>>a>>b>>n>>m; ll ans=min(a,b); if(ab){ ll tmp=(a-b)/(n+1); ans=max(ans,min(a-tmp*b,b+tmp)); } cout<