#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int a, b;
  cin >> a >> b;
  string c;
  cin >> c;
  char f;
  bool flag = true;
  for (int i = 0; i < a; i++) {
    f = c[i];
    if (f == '-') {
      flag = false;
      cout << "a" << endl;
    }
  }
  f = c[a];
  if (f != '-') {
    flag = false;
    cout << "b" << endl;
  }
  for (int i = 0; i < b; i++) {
    f = c[a + 1 + i];
    if (f == '-') {
      flag = false;
      cout << "c" << endl;
    }
  }
  if (flag == false) {
    cout << "No " << endl;
  } else {
    cout << "Yes " << endl;
  }
}
