#include <bits/stdc++.h>
const int ms = 1010;
long double memo[ms][ms][2];
bool visit[ms][ms][2];
long double dp(int n, int m, int t) {
  if (n <= 0 || m < 0) return 0;
  long double &ans = memo[n][m][t];
  if (visit[n][m][t]) return ans;
  visit[n][m][t] = true;
  ans = 0;
  if (t == 0) {
    ans = (long double)n / (n + m) + (long double)m / (n + m) * dp(n, m - 1, 1);
  } else if (n + m > 1 && m > 0) {
    ans = (long double)m / (n + m) *
          ((long double)n / (n + m - 1) * dp(n - 1, m - 1, 0) +
           (long double)(m - 1) / (n + m - 1) * dp(n, m - 2, 0));
  }
  return ans;
}
int main() {
  std::ios_base::sync_with_stdio(false);
  std::cin.tie(NULL);
  std::cout << std::fixed << std::setprecision(20);
  int n, m;
  std::cin >> n >> m;
  std::cout << dp(n, m, 0) << std::endl;
}
