#include <bits/stdc++.h>
using namespace std;
template <class A, class B>
inline bool chmax(A &a, const B &b) {
  return b > a ? a = b, 1 : 0;
}
template <class A, class B>
inline bool chmin(A &a, const B &b) {
  return b < a ? a = b, 1 : 0;
}
constexpr int INF = 0x3f3f3f3f;
signed main() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  bool f = (s[a] == '-');
  s.erase(a);
  f &= all_of(s.begin(), s.end(), [](int c) { return isdigit(c); });
  puts(f ? "Yes" : "No");
  return 0;
}
