#include <bits/stdc++.h>
const double PI = acos(-1);
const long double EPS = 1e-9;
using namespace std;
void solve() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  if (s[a] == '-') {
    for (int i = a + 1; i < a + b + 1; i++) {
      if (!(s[i] >= '0' && s[i] <= '9')) {
        cout << "No";
        return;
      }
    }
    cout << "Yes";
    return;
  }
  cout << "No";
}
int main() {
  int q = 1;
  while (q--) solve();
}
