#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  for (int i = 0; i < a + b + 1; i++) {
    if (i == a) {
      if (s[i] != '-') {
        cout << "No";
        break;
      }
    }
    if (!(s[i] <= '9' || s[i] >= '0')) {
      cout << "No";
      break;
    }
  }
  cout << "Yes";
}
