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