#include <bits/stdc++.h>
using namespace std;
const long long int MOD = 1000000007;
int main() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  for (int i = 0; i < (a + b + 1); ++i) {
    if ((i == a && s[i] != '-') || (s[i] < '0' || '9' < s[i])) {
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
  return 0;
}
