#include <bits/stdc++.h>
using namespace std;
template <class T>
using V = vector<T>;
using ll = long long;
using db = double;
using st = string;
using ch = char;
using vll = V<ll>;
using vpll = V<pair<ll, ll>>;
using vst = V<st>;
using vdb = V<db>;
using vch = V<ch>;
int main() {
  ll a, b;
  cin >> a >> b;
  ;
  st s;
  cin >> s;
  ;
  ch now;
  ll count = 0;
  for (ll i = (0); i < (ll)(a + b + 1); i++) {
    now = s[i];
    if (i == a) {
      if (now != '-') {
        cout << "No" << endl;
        count = 0;
        break;
      }
    } else {
      if (now < '0' || '9' < now) {
        cout << "No" << endl;
        count = 0;
        break;
      }
    }
    count++;
  }
  if (count == b + 1) {
    cout << "Yes" << endl;
  }
}
