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