#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  int flag = 1;
  for (int i = 0; i < b; i++) {
    if (s[a] != '-') {
      flag = 0;
      break;
    } else {
      if ((i > a || i < a) && !isdigit(s[i])) {
        flag = 0;
        break;
      }
    }
  }
  if (flag == 1) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
  return 0;
}
