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