#include <bits/stdc++.h>
using namespace std;
const int max_v = 300;
const int INF = 1000000;
int main() {
  int a, b, ans = 0, ten = 10;
  string s;
  cin >> a >> b;
  cin >> s;
  for (int i = 0; i < (int)(a); ++i) {
    if (int(s[i]) == 45) {
      cout << "No" << endl;
      return 0;
    }
  }
  if (s[a] != '-') {
    cout << "No" << endl;
    return 0;
  }
  int aa = a + 1;
  int bb = a + b + 1;
  for (aa; bb == aa; aa++) {
    if (s[aa] == '-') {
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
  return 0;
}
