#include <bits/stdc++.h>
using namespace std;
long long power(long long b, long long p) {
  if (b == 0) return 0;
  long long res = 1;
  while (p) {
    if (p % 2) {
      res = (res * b) % 998244353;
      p--;
    } else {
      b = (b * b) % 998244353;
      p /= 2;
    }
  }
  return res;
}
long long Root(long long r, vector<long long> &root) {
  while (root[r] != r) {
    root[r] = root[root[r]];
    r = root[r];
  }
  return r;
}
void EE(long long a, long long b, long long &x, long long &y) {
  long long t;
  if (b == 0) {
    y = 0, x = 1;
    return;
  }
  EE(b, a % b, x, y);
  t = x;
  x = y;
  y = t - a / b * y;
}
void build(long long node, long long start, long long end, vector<long long> &a,
           vector<long long> &tree) {
  if (start == end) {
    tree[node] = a[start];
    return;
  }
  long long mid = (start + end) / 2;
  build(2 * node, start, mid, a, tree);
  build(2 * node + 1, mid + 1, end, a, tree);
  tree[node] = tree[2 * node] + tree[2 * node + 1];
}
long long query(long long node, long long start, long long end, long long l,
                long long r, vector<long long> &tree, vector<long long> &lazy) {
  if (lazy[node]) {
    tree[node] = end - start + 1 - tree[node];
    if (start != end) {
      lazy[2 * node] = lazy[2 * node] ^ 1;
      lazy[2 * node + 1] = lazy[2 * node + 1] ^ 1;
    }
    lazy[node] = 0;
  }
  if (start >= l && end <= r) {
    return tree[node];
  }
  if (l > end || r < start) return 0;
  long long mid = (start + end) / 2;
  return query(2 * node, start, mid, l, r, tree, lazy) +
         query(2 * node + 1, mid + 1, end, l, r, tree, lazy);
}
void update(long long node, long long start, long long end, long long l,
            long long r, vector<long long> &tree, vector<long long> &lazy) {
  if (lazy[node]) {
    tree[node] = end - start + 1 - tree[node];
    if (start != end) {
      lazy[2 * node] = lazy[2 * node] ^ 1;
      lazy[2 * node + 1] = lazy[2 * node + 1] ^ 1;
    }
    lazy[node] = 0;
  }
  if (l > end || r < start) return;
  if (start >= l && end <= r) {
    tree[node] = end - start + 1 - tree[node];
    if (start != end) {
      lazy[2 * node] = lazy[2 * node] ^ 1;
      lazy[2 * node + 1] = lazy[2 * node + 1] ^ 1;
    }
    return;
  }
  long long mid = (start + end) / 2;
  update(2 * node, start, mid, l, r, tree, lazy);
  update(2 * node + 1, mid + 1, end, l, r, tree, lazy);
  tree[node] = tree[2 * node] + tree[2 * node + 1];
}
void dfs(long long r, queue<long long> &q, vector<long long> &st,
         vector<long long> &vis, vector<vector<long long> > &v) {
  vis[r] = 1;
  long long i;
  for (i = 0; i < v[r].size(); i++)
    if (!vis[v[r][i]]) dfs(v[r][i], q, st, vis, v);
  if (st[r]) q.push(r);
}
void dfs1(long long r, vector<long long> &vis, vector<vector<long long> > &v,
          long long &c) {
  c++;
  vis[r] = 1;
  long long i;
  for (i = 0; i < v[r].size(); i++)
    if (!vis[v[r][i]]) dfs1(v[r][i], vis, v, c);
}
double rec(double w, double b, vector<vector<double> > &dp) {
  if (b < 0) return 0;
  if (dp[w][b] != -1) return dp[w][b];
  if (w == 0) return dp[w][b] = 0;
  if (b <= 0 && w) return dp[w][b] = 1;
  if (b <= 0) return dp[w][b] = 0;
  double res;
  if (w + b == 2) return dp[w][b] = .5;
  res = w / (w + b) + b / (b + w) * (b - 1) / (b + w - 1) *
                          (w / (w + b - 2) * rec(w - 1, b - 2, dp) +
                           (b - 2) / (w + b - 2) * rec(w, b - 3, dp));
  return dp[w][b] = res;
}
int main() {
  ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  srand(time(NULL));
  ;
  double w, b, res;
  cin >> w >> b;
  vector<vector<double> > dp(w + 1, vector<double>(b + 1, -1));
  res = rec(w, b, dp);
  printf("%.15lf", res);
}
