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