#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  int a, b;
  cin >> a >> b;
  cin >> s;
  s = ' ' + s;
  if (s[a + 1] == '=') {
    cout << "Yes";
  } else {
    cout << "No";
  }
  return 0;
}
